W3C Annotation Architecture proposalA diagram that explains the relationship of authors, publishers, readers, documents, annotations, and annotations servicesW3C Annotation Architecture proposalimage/svg+xmlDoug SchepersShepazuW3C
License: CC-BY (Creative Commons Attribution)
Web Annotation Architecturenextprevious
This interactive infographic explains a proposed
architecture of W3C Web Annotations, as part of anongoing conversation with the annotation community.To read the detailed explanations of this diagram,
use the “down” key to move to the next step,and the “up” key to move to the previous step,or use the next/previous buttons.Content CreatorThe Content Creator makes the original text,images, and other resources, often collaboratively orwith review cycles. There may be more than one ContentCreator responsible for a single work.PublisherThe Publisher (which may be the same entity as theContent Creator) distributes the content on the Web,in ebooks, etc.The content is published in near-final form, with a URL orother unique locator (such as an ISBN for an ebook).Footnotes & CommentsFootnotes and comments may be added to the content.Both may be considered as a kind of annotation, beingmeta-content, and both are implicitly published by thesame publisher as the content, at the same location.Footnotes may be anchored to a particular section ofthe content, and may or may not have differentprovenance than the main content, such as a differentauthor, or a different publication time and date.Reader comments on the content traditionally lack an anchor to a specific section of the content; some modern commenting systems allow comments at the paragraph orsentence level. Quality comments increase the value ofthe original content through corrections, additionalinformation, or relevant links, and increase reader and community engagement. Publishers control whichcomments are published, which is often hard to manage.ReaderThe Reader plays a critical role in the content ecosystem,interacting with the content in a number of ways.The Reader reads, analyzes, and thinks about thecontent. But this is only the beginning.Creating Web AnnotationsAnnotations provide a more powerful way for anactive Reader to comment, correct, highlight, orcategorize content selections.With annotations, a Reader can target a discreteselection.A selection can be text, a section of an image, a locationon an interactive map, a timestamp of a video or audio, or a data representation that has an underlying data source.A Reader can even annotate a footnote ...... or a traditional site comment. (Very meta.)Other readers can annotate sections of content thatoverlap existing annotations ...... and even annotate annotations themselves, inthreaded replies.Distributed publication of Web AnnotationsWhen a Reader creates a Web annotation, they don'thave to publish it on the original content site; theReader can publish their annotation content on one ormore third-party “annotation services”, or on the Reader'slocal device.This decentralization is one of the key features of Web Annotations, giving the Reader (who is now a ContentCreator) their choice of Publishers, reader communities,and publishing policies. This helps promote healthycompetition between services and discourages publisherlock-in. Individuals or special-interest communities caneven host their own annotation services.Notifications of annotation sent to PublisherThe Publisher receives a notification for anyannotations made on their site which are explicitlypublished publicly.There are two proposed mechanisms for this:1) a client-side event which informs thepage of the annotation's publication URLs;2) a server-side notification sent to the publisher's“well-known” contact address.Either or both of these mechanisms may be used, eachwith its own use cases.Publisher queries, fetches, and republishes
annotationOnce notified of an annotation, the Publisher canrequest more information about the annotation fromthe annotation service through the proposed HTTP API,including author credentials, the reputation of theannotation (“karma” or “up-votes”), publication license,and other details that might lead to an informed decisionabout the value of the annotation. If the Publisher wishes, they can fetch the annotation itself.Once requested, the annotation service sends thePublisher the annotation.The Publisher can then publish the annotation as acomment. This maintains the Reader-provided valuefor Publishers, while still allowing distributed annotationpublication.Reader discovers and subscribes to
annotation feedsAnnotation services offer a better way for a Reader todiscover new primary content, new discussion aboutcontent, new individuals or communities, and newannotation services. Web annotations are ideally seen inthe context of their target content, but annotationservices can offer a view of each annotation alone or in acollection or stream (as with services like Reddit, Twitter,or Facebook). Readers can do faceted searches that spanmultiple annotated sites, for specific topics or hashtags,for content from a particular person, or more tasks thatwould be difficult with siloed site-specific commentsystems.Once a Reader discovers an interesting person, topic,community, or service, they can then subscribe tohave those annotations delivered to their browser whenthey visit a relevant URL. Annotation subscriptions may beproxied by aggregators or federated annotation services.Web Annotations loaded when user visits
target pageEach annotation includes the annotated content's originalURL, so a Reader with annotations enabled can read anyof these annotations when visiting that URL. Theannotations are loaded from one or more annotationservices, displayed on the page (such as in a sidebar),and dynamically anchored to the specific contentselection, showing the annotation in context, andenabling discussion even for sites without nativecomments.Currently, this functionality is only available throughJavaScript browser extensions (like the open-sourceAnnotator project), but the ultimate aim is nativebrowser support, both for loading annotations for anyURL, and for anchoring them to the selected content.Other readers share annotations, with
provenanceWhen someone finds an annotation that they like (ordislike), they can share it with others, by sharing theannotation's unique permalink, republishing theannotation, or annotating the annotation with their owncontent; even “up-voting” or tagging an annotation is anact of annotation and sharing. The Open Annotation datamodel provides a standardized way to represent anannotation, so any Web annotation can be shared on thesame annotation service or on a different interoperableannotation service.Shared Web annotations include provenance, so theywill always have a link back to its original URL, andeven a chain of attribution that shows everyone whoshared it in a sequence. This is an important way tospread content while rewarding the original ContentCreator.contentcreatorpublisherreaderweb annotation serviceswritesend-to-publisherpublishpublishreadannotatepublish annotationpublish annotationpublish annotationnotificationnotificationHTTP API requestHTTP APIpublish commentdiscoversubscribesubscribesubscribesubscribeload annotationsload annotationsload annotationsshareattribution chain