This document describes the set of use cases generated for Annotation
and Social Reading within the W3C
Digital Publishing Interest Group, in coordination with the Open
Annotation Community Group.
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This section describes the status of this document at the time of
its publication. Other documents may supersede this document. A list
of current W3C
publications and the latest revision of this technical report can be
found in the W3C
technical reports index at http://www.w3.org/TR/.
This is a work in progress. No section should be considered
final, and the absence of any content does not imply that such content
is out of scope, or may not appear in the future. If you feel
something should be covered here, tell us! The initial
version of this document will focus on books, and at this time will not
include requirements specific to magazines or newspapers. The scope will
depend heavily on the willingness of people to contribute to this
document. Please contact the Digital Publishing Interest Group if you
would like to help.
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The disclosure obligations of the Participants of this group are described in the charter.
This section is non-normative.
Annotation is a pervasive activity when reading or otherwise engaging
with publications. In the physical world, highlighting and sticky notes
are common paradigms for marking up and associating one's own content
with the work being read, and many digital solutions exist in the same
space. These digital solutions are, however, not interoperable between
systems, even when there is only one user with multiple devices.
This document lays out the use cases for annotations on digital
publications, as envisioned by the W3C
Digital Publishing Interest Group, the W3C
Open Annotation Community Group and the International Digital Publishing
Forum. The use cases are provided as a means to drive forwards the
conversation about standards in this arena.
The use cases are divided into five sections: annotations that target
only the entire publication, annotations that target a particular part
of a publication, more complex annotations, the publication of
annotations and finally use cases that are directly related to
2.1 Annotations Targeting the Full Publication
2.1.2 Tagging a Publication
A user wishes to organize their personal digital library by
tagging the publications that they have access to. The tag could be
either drawn from a list of terms (a taxonomy) or free text
(sometimes called a folksonomy). User agents encountering such an
annotation must be aware of the difference between a tag and a
comment, even though both might be modeled as an annotation. Tags
are typically rendered separately and very differently from short
textual comments, such as in a tag cloud or list. The user then
wishes to view their library partitioned via the tags. The user may
wish to share their tags with other users to help the recipient
categorize their own library, or find publications of mutual
- Colleen has a collection of works of various types in her
library about chemistry, science fiction and the renaissance. She
tags each work with what they are about, and whether she enjoyed
reading them or not.
- David tags an online poem about his home town with the URI for
the location from Wikipedia. He publishes this annotation so that
others can find it.
2.1.3 Structured Review of a Publication
A user wishes to provide a structured review of a particular
publication, including pre-defined fields such as "star" ratings for
quality, cost, entertainment or other domain-specific information.
The review could also include a full text description, such as the
comment in the first use case. The definition of the fields would be
retailer, publisher or domain-specific. In the scholarly domain,
this could be expected to provide a distributed and standardized
peer-review system, rather than the current use of vendor-specific
interfaces. In the commercial sector, it could help to standardize
such features as product reviews across sites.
- Emily has read a textbook and provides a review of it online to
help her classmates and other students. She gives it ratings on
value for money, ease of use, ease of understanding, and overall
quality, plus a long form description of the work.
- Fabio is reviewing a scholarly article for an academic
publisher. The publisher requires various fields to be completed,
such as relevance to the journal, novelty of the research, and
quality of the experiments described. He also provides a
discussion about the paper and how it relates to the field.
2.1.4 Comment Maintained Separately from
A user wishes to link an existing web resource, such as a blog
post or uploaded video, to the particular publication that it is
about. The comment could be any online resource, in any format. The
user wishes other readers to be able to see the resource linked to
the publication, and potentially before they purchase or download it
as well as afterwards.
- Gretchen uses a mobile device to take a video of herself
discussing a work that she has just read for a book club. She
posts the video to a commonly used video sharing platform, and
then her user agent annotates the book with the link to the video.
She then shares the annotation with the members of her book club.
- Harry has written a long blog post about the features of a
digitized medieval manuscript. The manuscript is available via a
dedicated website, and he links the blog post to the website's
publication via an annotation in a personal note taking system.
2.2 Annotations Targeting Specific Segments of
2.2.1 Bookmarking Current Reading Position
A user wishes to have their user agent record the location they
have read up to in the publication, either with a manual or
automatic bookmark. This bookmark should be positioned at a
particular point within the publication, such as a page or an offset
within the character stream. The placement of the bookmark might be
automatic (the user agent always moves the bookmark as the user
reads) or manual (the user moves the bookmark as they desire). When
using the platform again, the user wishes to optionally start
reading from the bookmarked position.
The user also wishes to share this position with others to show
how far through the publication they have progressed. This might be
publically shared for bragging rights, shared semi-publically such
as a reading group or class, or shared privately between platforms
that the user has access to in order to maintain the position
- Madeleine is reading a fantasy book as she commutes to work on
the train every day. When she closes her mobile device, her
reading system automatically bookmarks where she was reading so
she can resume from that position when she gets the train home in
- Nigel is studying for an exam and creates bookmarks in his
textbooks and required reading documents at home. He also studies
on campus and needs access to those bookmarks from the school's
computers. He does not want other students to see his bookmarks,
as he is competitive and wants to be the top of the class.
2.2.2 Highlighting a Span of Text
A user wishes to highlight a span of text in a publication for
emphasis. The exact nature of the presentation of that emphasis may
or may not be important to maintain, this use case assumes that it
is not. The emphasis might be to mark a passage of particular
importance, a typo or other mistake, something to cite in another
document, to bring to the attention of other readers, or to mark two
such selections for comparison. The user may wish to share the
highlight, and certainly wishes it to be accessible on multiple
platforms to which she has access. In this use case there is no
requirement to provide a comment or body of the annotation, simply
to record a highlighted span of text.
- Olivia is preparing to publish a newspaper article and is doing
background research. She highlights various sections of other
publications in order to later come back to them and decide if she
should include them as quotes in the article or not.
- Peter is proofreading his own term paper and highlights areas
that he needs to work on. He does this on a mobile device, but
later needs to see those highlights in his word processing
2.2.4 Annotating Embedded Resources
A user wishes to make a comment about a particular resource that
is embedded as part of the publication, such as an image or video.
In the general case, the user would expect to somehow select the
embedded resource and then launch the interface for adding comments
in the same way as commenting on text. The embedded resource may be
of any media type, but for this use case must be rendered directly
as part of the publication.
- Siobhan is reading a comic and comments on a particular image
that it is much darker than the other cells in the publication.
- Thomas is reading a white paper that includes an embedded
dataset. He tags the dataset with a semantic URI identifying the
subject matter of the dataset, which is different to the paper as
2.2.5 Annotating Parts of Embedded Resources
A user wishes to annotate a particular part of an embedded
resource, such as a rectangular section of an image or a particular
time range of an embedded video file. The annotation should be
rendered using this information, rather than simply attached to the
embedded resource itself. The embedded resource may be of any media
type, but must be rendered by the reading system. Thus video, image,
audio and similar are in scope for this use case, but not
stylesheets or scripts which are not rendered directly. Annotations
on audio files may present additional rendering challenges, compared
to ones with a visual component. The user then wishes to share the
annotation with others.
The parts of resources to be annotated include:
- Character position in an embedded text or data stream
- Time position within an audio or video stream
- x/y points in an area such as an image or video
- x/y/z points in a volume such as a 3d object
- Character ranges within a text or data stream
- Time ranges within an audio or video stream
- Areas within an image, including rectangular, circular and
- Volumes within a 3d object
- Umeko is teaching a class on physics and annotates part of an
embedded video within the electronic textbook, delineating the
time range that she wants to use as an example. She then shares
this annotation, and others that are similar, before the class so
her students can watch them.
- Vladimir is reading an online magazine about fashion and
annotates part of one of the images that depicts a particular
style he wishes to replicate in his own work.
2.2.6 Annotating Alt Text of Embedded
A user wishes to write a comment about a resource embedded within
the publication, and to associate it with alternate, accessible
representations of that resource, such as the alt text/long desc
provided. The comment may be only about part of the alternate
representation, and thus segments of the alternate representation
must be able to be selected. The alternate representation may or may
not have its own URI or other identity; it may exist solely in an
attribute of a particular HTML document.
- Whitney is concious of accessibility and annotates the depiction
of a friend in a photograph, and wants to align that annotation
with the name of the person in the textual description of the
photograph in her school yearbook. The text description is
provided in the alt text of the image element.
- Xavier is annotating a video. He associates his comments about
linguistics with both the time range of the video, but also the
accessible text transcription of the speeches.
2.2.7 Annotation Comparing Segments within a
A user wishes to annotate two or more parts of a publication,
embedded resources, or part of an embedded resource, in order to
compare or contrast the targets. This may be to point out
inconsistencies in the content or rendering, to make a note about
two similar or related passages, or to link part of an embedded
resource to where it is referenced in the text.
- Yadira is studying a book for an English class and highlights
the sections where the author is talking about the age of a
character, to demonstrate that the author is inconsistent. She
makes the case in the comment that this is intentional.
- Zahir highlights areas in charts within a scientific article
that demonstrate a particular fact related to his own work. He
comments with a personal note to this effect.
2.2.8 Annotation Comparing Segments between
A user wishes to annotate two or more parts of different
publications in order to compare or contrast the targets. This may
be to make a note about two similar or related passages such as
plagiarism, or to link part of an embedded resource to where it is
referenced elsewhere. For example, the user may wish to link
appearances of the same character in multiple books, popular
references to prior works, or examples of passages that contradict
each other in scholarly literature.
- Ahmed discovers three news articles about the same event which
give very different accounts. He selects the disagreeing numbers
given in each, and comments that he believes the lowest of the
three and gives his rationale.
- Bianca is linking the transcriptions of song lyrics, published
in various anthologies, together based on obscure references to
particular real world people. She tags the segments with the
person's identity in Wikipedia.
2.3 Advanced Annotation Use Cases
2.3.1 Cross Format Annotations
A user wishes to annotate a digital publication in one format and
have the annotation appear for different representations of the same
resource. For example, an annotation created on an EPUB should also
be rendered on the equivalent PDF or HTML page. The annotation can
be either on the publication level, or anchored to a particular part
of the text. Annotations on embedded resources (such as images) that
are embedded without identity in alternate representations are not
considered in scope, for example annotating a part of an image in an
HTML page which is then embedded within the PDF representation of
- Craig is reading a book on motorsports that is published both
online and reproduced as a PDF. He publishes an annotation about a
span of text in the HTML version, and expects that it will appear
in his tablet based reading platform after synchronization, where
the same article is a PDF.
- Dee reviews a scholarly article in a dedicated client on her
computer, where the article is a print-ready PDF. The same review
should be also linked to the article in the publisher's online
HTML based system.
2.3.2 Cross Version Annotations
A user wishes to annotate part of a publication for which she has
multiple editions, or that is updated regularly, and have those
annotations persist between versions of the same publication. If the
publisher provides a new version of a publication, known to happen
silently at times for various reasons, then the annotations about
the publication should be available on this new version rather than
equally silently disappearing. As with any annotation that should be
presented with more than just the resource it was created for, cross
versioning allows for a wider audience and thus is a potential
target for spammers.
- Enrique wishes to annotate the first line of Hamlet in such a
way that it should appear on all of the copies of the play that
the user has access to, rather than just the particular version
that was open when the annotation was created.
- Faith is a teacher who wishes to annotate a text book in such as
way that her annotations are visible to her students even though
they do not have the exact same version, but instead have acquired
it from different retailers.
This use case is particularly challenging to solve in environments
in which identifiers for the work, rather than the particular
version, do not exist.
2.3.3 Maintaining Annotation Style
A user wishes to associate a particular style with an annotation,
either for the comment or the delineation of the target of the
annotation. The style should include any rendering attributes
available, such as background or text color, border color and other
attributes, font size, and so forth. When colors or styles
associated with annotations are meaningful to an individual, to a
particular group, or just generally, a text label should be able to
be associated with the annotation drawn from a list of terms
(taxonomy) or free text, in order to assist with accessbility.
- Gerard draws a bounding box on an image of the night sky, and
wishes to ensure that his client in the future will draw the box
in bright green to stand out, and certainly not to draw it in the
default black which would be unable to be seen.
- Hailee highlights parts of a non-fiction text in two colors that
have meaning to her; red strikethrough is statements that she
disagrees with, and green background is for statements that she
does agree with. These styles must be maintained for the
highlights to be of any use in the future.
2.3.4 Maintaining Annotation Layout
A user wishes for their annotations to be presented at a
particular location on the page, such that the layout of the
annotations doesn't interfere with the reading of the publication.
For example, annotations could be styled as a particular height and
width, and then put into the margins of the page or over top of
other white space. Annotations could be visually ordered such that
reading them in the presented order gave a better experience than
reading them in the order of the targets within the publication.
Thirdly, the layout could be used for organization of thoughts
concerning the publication by moving all of the related annotations
together spatially. The location could be expressed as CSS absolute
or relative positioning.
- Ichiro is reading a fixed-layout work and positions his
annotations above whitespace in the text with arrows to the
character span that they refer to. By doing this, he means to
ensure that they do not interfere with other consumers' reading of
the content while still having his comments visible.
- Jacinta is a publisher and lays out the author's annotations on
a novel in such a way that they aid the reader in understanding
how the author was thinking about his characters. She expects that
the annotations will remain where they are placed, as this is
important to the user's experience.
2.3.5 Recording State of Changing, Online
A user wishes to annotate the publication as it appears with
dynamic resources in a particular state, or in terms of the web
architecture, given a particular representation. Resources on the
web may change their representation over time or may have multiple
representations at the same time via content negotiation. The URI of
the resource alone is thus not sufficient to determine the
representation that was delivered to the annotator, and additional
information such as the time of the request and the HTTP headers
sent must be recorded.
- Ken annotates an online travel publication that is frequently
updated with the latest information, such as the prices of hotel
rooms and the quality of restaurants in the area. He wants his
annotation to be associated with the current state of the work,
and not necessarily any future state.
- Lynda is reading a book that dynamically embeds images via a
service. The JPG format that is used by a particular publication
is rendered with too high a compression level, and it is hard to
understand compared to the original PNG format. She thus wishes to
comment only on the JPG that it is hard to see, rather than on the
PNG which shares the same negotiable URI.
2.3.6 Recording State of User Manipulated
A user wishes to annotate a publication with embedded, dynamic
resources. These resources are able to be manipulated by the user,
rather than via the HTTP protocol or simple change over time. Some
number of manipulations must be performed in order for the target of
the annotation to be visible or understandable, regardless of the
accuracy of the description of the target segment. The consuming
user agent should then be able to reproduce these manipulations in
order to allow a third party to see the resource as annotated.
- Maurice is studying a publication that embeds a 3 dimensional
model of a protein structure that can be rotated, panned and
zoomed. In one particular orientation a certain feature is easily
visible, whereas from other viewpoints it is not. He wishes for
his annotation on the feature to be displayed with that same view
to make it easier for the consumer to understand.
- Nadia highlights some text in a page that is responsive to user
interactions and preferences. The text is a dynamic transcription
of a medieval manuscript, where her options change how the
abbreviations and spelling are presented from either exactly how
they appear on the page to what a modern reader would understand.
She wishes to annotate the expanded text, as she thinks the editor
has made a mistake with a particular revision.
This use case is particularly challenging to solve in the generic
case rather than with media specific solutions.
2.3.7 Annotation has a Choice of Multiple,
Dependent Bodies or Targets
A user wishes to annotate a publication or part thereof with
multiple options for the body or target. The options are thus
dependent on each other, and only one of the options should be
displayed to the user. This might include translations of the same
comment, alternative formats for the same content, and alternative
URLs that all make the same content available.
- Owen speaks both Japanese and English, and wishes to provide
translations of his comment in both languages. He teaches English
as a foreign language in Japan, and his students should be able to
choose whether to view it in one language or the other.
- Petra annotates a paper that is published in multiple locations,
however the representations are identical. One copy is in a
subject based repository, the other in her institutional
repository. She wishes to explicitly link both of the targets to
ensure her annotation can be presented along with at least one
copy of the paper from the most convenient location to the
2.3.8 Annotation has Multiple, Dynamically
A user wishes to target segments of a resource that appear more
than once in that resource, termed here a "repeated segment". The
user does not necessarily know the exact number of times the
repeated segment appears in the resource; the interpretation of the
annotation is understood to be independent of the number of
instances of the repeated segment.
- Quinn, a copy editor, creates an annotation proposing a
correction to replace all instances of the string "pleaf'd" with
the string "pleas'd". Essentially the annotation is proposing a
search and replace operation of the sort ubiquitous in modern word
- Romana, a manufacturer, wishes to annotate all products of a
certain class in his products database with a note that these
items will go on sale next week for 15% off for 2 weeks only.
There are usability implications with annotating dynamically defined
segments, rather than specific enumerated segments. This could be used
as an attack vector for spam or exploitation of user agent bugs by
annoting common words on frequently visited URIs. For example,
annotating "a" on the top million sites with an advertisement in the
2.3.9 Determination of Annotation Validity
after Target is Modified
A user annotates a publication with a correction to the text. The
publisher then acts upon this annotation to correct the mistake, or
in the scholarly field potentially to retract the publication from
the scientific record. After the correction has been made, the
annotation no longer applies to the publication and hence should not
be displayed. It may be important not to delete the annotation, such
that the user gets credit in some system for reporting the
correction. The system that maintains the annotation may not be
connected to the system that publishes the publication, and hence
might not be able to be updated.
- Solomon annotates a gaming manual with a correction as to which
controls are needed to perform a particular move. The publisher
re-issues a new copy of the manual after the correction has been
made to avoid other users having the same frustration. Quinn's
annotation should not appear on the new version.
- Teynika annotates a typo in how her name is spelt (two 'n's
instead of one) in a book about the research in her field. Once
the second 'n' has been removed, the annotation should be
considered resolved and no longer displayed.
This use case is particularly challenging to solve in the generic
case rather than within specific systems that understand the
motivation of the annotation and when it has been resolved.
2.3.10 Determination of Annotation Validity
for Embedded Resources
A user annotates an embedded resource, such as an image, which is
used in several places within a publication. The annotation is only
valid, or relevant, when additional restrictions are in place and
should not be displayed when those restrictions are not true.
- Ulrich reads a publication in which the same headshot photograph
is used for two different people and wants to annotate the
photograph to say that it is wrong when used on page 1, but not
have the annotation displayed when the photograph is used
correctly on page 3.
- Veronica wishes to comment that a company logo should only be
used in the header on every page, but nowhere else.
2.4.1 Sets of Annotations for a Publication
A publisher has one or more sets of annotations about a
publication and wishes to supply those annotations along with the
publication. Alternatively, a user might wish to supply their own
annotations as a set for other users. These annotations could be
comments by the author (in the same vein as DVD extras commentary),
from famous readers, or simply pointers to related works. In an
education setting, this functionality could be used to provide
additional commentaries on a text book or other publication that are
intended to assist the student in understanding the material. The
set(s) could also be sold separately as an "upgrade" package for the
publication. The order of the annotations may be important, for
example to read the publication in chronological rather than
narrative order, or by following the order of a class lectures
rather than the order of the chapters in the text book. The metadata
about the collection of annotations is also important, such as who
packaged them together and for what purpose.
- Wesley works for a publishing house and has transformed the
author's commentary on their steampunk novel into a set of
annotations for sale. The company wishes to have them available as
an add-on for customers that have already bought the novel, and
also in a bundle for new sales.
- Xena is a PhD student studying a famous detective story set in
London. She works out a walking route that takes the user through
all of the locations in the book in an optimal fashion, which is
not the same order as the narrative, and wants to publish her
annotations about the locations in that sequence.
2.4.2 Persistence of Annotations
A user wishes to save the annotation that they have created in
order to retrieve it later, regardless of whether it is finished or
not. The Annotation should be given a unique and resolvable
identifier. The user may wish to save the annotation in their own
system, rather than the system which provides the resource being
annotated. The user may equally wish to save the annotation in
multiple systems. The annotation should persist in local storage if
the user is offline, and be persisted globally once the connection
is re-established. In the interim, a locally unique identifier
should be assigned to the annotation. Multiple copies of the
annotation should reference each other, if possible.
- Yasir writes an annotation about an astronomy publication and
wants to save it both in his own system and remotely for others.
- Zoe writes an annotation about Greek mythology which becomes
popular and is syndicated widely across many systems after its
initial publication online. The syndicated copies refer back to
the original source, which Xena uses for credit towards promotion.
2.4.3 User or System Initiated Transfers
Either the user or the system requests that all or some subset of
annotations that are maintained be transferred to another system. If
the user requests it, then it this enables an export functionality
such that the user's annotations can be exported to another platform
or device. If the system requests it, then this enables a
synchronization functionality where the user's annotations will be
maintained in multiple locations for ease of use and preservation,
or aggregation for analysis. Both such cases should use the same
- Anya has two devices that are on the same network. The devices
are set to synchronize his annotations whenever they detect each
- Bob has written a lot of annotations on a plane trip while
offline. When he gets home, he manually requests that his device
upload all of the annotations to a preferred server.
2.4.4 Annotation (or Part) is not Published
A user wishes to keep their annotations or personal notes private,
or only share with a small group of people such as a reading group,
academic research group or only with a set of friends in a social
network. Even if the user wishes to keep their annotations private,
the ability to transfer the annotations between devices is
desirable, so that they be used regardless of the particular reading
The user may also wish to keep only some aspect of the annotation
private, for example the comment should be protected, while the
annotation graph can be shared openly, or vice versa. Regular web
based authentication and authorization structures should be used to
enable this functionality in an online environment to ensure
- Catherine publishes her annotation on the effects of a
particular pharmaceutical product in an authenticated environment
in which only her and her colleagues can see it.
- Doug publishes his annotation openly so that other systems can
see the linkage between the resources, but the comment itself is
protected by an authentication system and paywall.
2.4.5 Publication (or Part) is not Published
A user wishes to annotate a resource the she has access to, but
requires authentication and/or authorization to view or annotate.
The annotation should not circumvent or allow the circumvention of
this DRM, for example by reproducing the content of the target
- Elana annotates a closed access journal article that she has
access to while at university. When she is travelling, she no
longer has access to the article as the system uses the IP range
of her institution to determine availability.
- Frank works for the closed access journal publisher and is
concerned that the annotation Elana made quotes some of the
protected text, and if someone were to annotate the entire text,
it would break their authorization model.
2.5 Accessibility and Internationalization
2.5.1 Using Annotation for Contributing
An annotation provider (personal or retailer) wishes to provide
annotations that give additional information about resources for the
purposes of accessibility.
- Gabby annotates an image with an audio file that records her
description of the image. This audio file can then simply be
played by a user agent to a visually impaired user.
- Hadrien annotates the text transcription of a segment of video
to the appropriate place in the video stream. The transcription
can be displayed to someone unable to hear the audio part of the
video, or when the user agent does not have sound capability.
2.5.2 Location of Annotations
Users need to easily become aware of and find highlights or
annotations, particularly when using a screen reader, a small
screen, or seeking sparse annotations in a lengthy work.
- Isabelle is reading a long work about warfare that is not
heavily annotated. She wishes to skip ahead to the next
interesting section, and thus needs to have some way to visualize
the location of the annotations that others have made on the work.
- Jason is using a screen reader, and wishes to have the option to
listen to the annotations when they are available or to skip past
them. Whenever the system encounters an annotation it gives an
audio clue that tapping the screen will prompt the device to pause
reading to convey the content of the annotation.
2.5.3 Using Annotation for Contributing
A user wishes to provide internationalization information for a
document that they don't conrol, such as a translation for a
particularly complex phrase, or whether automated translation
systems should explicitly not translate a given phrase.
- Katelynn has implemented a machine translation system that
generates reliable Dutch translations and has it scheduled to run
on commonly updated English-language sites, before publishing to a
well-known annotation server in the Netherlands.
- Luke is a scholar in Ancient Greek, and routinely provides
translations for online texts when they have been transcribed from
museum objects. He wishes to make his translations available to
both the museums and anyone who visits their online exhibitions.
The following requirements are summarized from the use cases
- Identity of Annotation
- Identity of Publication (or Target Resource)
- Identity of Comment (or Body Resource)
- Identity of Resources Embedded within the Publication
- Multiple Formats for Comment, including Structured Data
- Distinction between Tag and Comment, or other types of Body
- Annotations without a Body Resource (Bookmark, Highlight)
- Metadata about the Annotation
- Ability to target a point within a Publication
- Ability to target a range of characters within a Publication's
- Ability to target an Embedded Resource
- Ability to target a segment (point, range, area, volume) of an
- Ability to target alternate accessibility representation of an
- Ability to target multiple resources with a single Annotation
- Ability to provide multiple resources as the body of a single
- Ability to specify that only one of the resources is required or
should be rendered
- Ability to specify that all of the resources are required or
should be rendered, perhaps in a particular order
- Ability to associate style information with bodies and targets
- Ability to associate timestamps with bodies and targets to
determine the appropriate representation
- Ability to associate HTTP request information with bodies and
targets to determine the appropriate representation
- Ability to have robust annotations that reference the same work
in different media types
- Ability to determine the validity of annotations in a dynamic
- Collection of annotations, where the annotations in the
collection are ordered
- Metadata about the Collection of Annotations
- Discovery of Annotations Relevant to Publication
- Persistence of Annotations
- Service for Sharing Annotations, either with others or between
- Management of Shared Annotations
- Authentication and Authorization in the Annotation ecosystem