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Use Case Social Annotation

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Social Annotation


Uldis Bojārs

Background and Current Practice

People create annotations to the information they are consuming (e.g., books or research papers). In the past these annotations were recorded on paper but increasingly they are being created electronically and published online.

Annotations may refer to objects at different levels of granularity. Some annotations describe the work (e.g., a book) as a whole while others annotate chapters or short sections of the text (paragraphs, sentences, words, pages...). Annotations may quote the content they refer to and add some additional information about it (e.g., reader's comments). Bookmarks and linemarkers -- which mark position but do not add text -- are also considered annotations.


  1. users are able to create, publish and share annotations about books and other works;
  2. available annotations can be aggregated and presented to users.

Linked data enables us to describe and publish annotation metadata, so that it can be reused (e.g. aggregated).

Target Audience

End users, librarians, software applications.

Use Case Scenarios

Creation and Publishing

1. user chooses the item that the annotation refers to

  • the item can be the whole work or its fragment (section, page, paragraph, word, etc.)
  • the item may be a physical thing (e.g. a book) or an electronic object (e.g., an e-book)

2. user creates the annotation by entering some information related to the item selected; a record of the annotation is created (i.e. it is saved).

  • a simple annotation may be a quote from the original content (similar to highlighting a text)
  • annotations usually contain a short description related to the item
  • annotations may also use other media than text (e.g., an image or a voice recording)

3. user publishes the annotation and (optionally) shares it with others

  • annotations may be private, shared publicly, or shared within a group of people
  • publication of annotations can be centralized (e.g., on a social networking site) or decentralized (on people's webpages)


Applications aggregate together multiple annotations and present them to users (end users, librarians, etc.). These annotations can be selected and viewed in multiple ways:

A) work-centered:

  • when looking at a page about a particular work (e.g., a book) users can see all [public] annotations referring to this work
    • for works in electronic form, highlights and notes made by others can be shown inline (e.g., when a user is looking at a particular page in an e-reader)

B) people-centered:

  • see the annotations shared by your friends
    • discover interesting thoughts and new works to read
  • aggregate together person's annotations (which may be distributed over the Web)

Social annotations may also be used for ranking works:

  • e.g. books that have the highest number of annotations

Ereader use-cases from Open Bookmarks


(from Open Bookmarks use cases) Dave uses an eReader to read a book. During the course of reading he makes a number of bookmarks. At a certain point, either before or after finishing the book, he exports his bookmarks, as well as attention data such as start/finish times for individual reading sessions. This data is saved as a separate file outside the eReader.


(from Open Bookmarks use cases) Importing Data

Dave reads half of a book on one eReading platform, making several bookmarks and exporting these as above. He then acquires a different eReader, and continues reading the same book. He imports the previous bookmarks into the new eReader, and they appear in the text.


(from Open Bookmarks use cases)

Dave is reading a book on an eReader. He is also a member of a third party social reading website. Periodically, the eReader syncs his bookmarks to the third party service. He can then view, share, save etc all of his bookmarks on the third party site. The data is transferred between the two platforms in the Open Bookmarks standard.

Sharing bookmarks

(from Open Bookmarks use cases)

Dave is teaching a class on a book. He annotates the book with his own notes, exports the bookmarks, and sends them to his students, who each import them to their eReader of choice.

Machine-readable annotations

(from Open Bookmarks use cases) Dave is reading an ebook, and notices that one of the words in the book is obviously incorrect, and probably an OCR error. He creates an annotation asserting the proper text at that location. The ebook publisher collects similar assertions for books it publishes, and uses them to correct OCR errors when publishing updated versions.

Application of linked data for the given use case

Linked data can be used for:

  • identifying works to annotate
  • fine-grained annotation -- pointing to fragments of a given work
  • publishing and aggregating annotations

1. Many publications already have URI identifiers and some have metadata available as linked data. These can be used for:

  • using common identifiers to point to works, facilitating annotation aggregation;
  • bootstrapping annotation applications by filling in information from the available work metadata.

2. A way to define fine-grained locations within / fragments of works is needed.

  • URI schemes or RDF properties developed for identifying locations / fragments of works can be created
  • this is an open problem (see Problems and Limitations)

3. By publishing annotations as linked data users make them available for easy aggregation and reuse

Existing Work (optional)

  • OpenBookmarks
    • a project to discuss and develop standards for saving, storing and sharing bookmarks, annotations and reading data in ebooks
    • in March 2011 the project changed its focus towards producing a [single document] Manifesto for Social Reading.
      • goal of the manifesto is to provide "a set of basic principles, that readers, publishers and developers can all understand, and the latter can implement in the way they feel is best".
  • bQuot - bookmark a quotation

Annotation Examples and Analyses

Related Vocabularies (optional)

Problems and Limitations

Note: a simple version of this use case is to implement work-level annotations only. This version can be achived by existing RDF vocabularies (and is probably already implemented).

Specifying Fragments of Works

The largest difficulty of this use case is specifying specifying positions (fragments) inside work at various levels of granularity.

  • we need URI schemes or RDF classes/properties for identifying locations / fragments of works
    • has to work both for electronic and printed works

Is there existing work that solves this problem?

Once a way to describe positions inside work is in place, the next issue is the correspondence of positions in different versions of the same work:

  • paperback vs. hardcover; e-book vs. printed book vs. audiobook; different editions
  • mediation services may be created to map position identifiers b/w different work versions
    • these services can be automatic (e.g., publishers provide mappings) or human-powered (volunteers help to link annotations between versions -- feasible if the no of annotations is small)


Annotation filtering and ranking may be required when the amount of annotations becomes large:

  • to recommend best annotations, their authors, etc.;
  • to combat spam.

Related Use Cases and Unanticipated Uses (optional)

Note: add links to other Use Cases that describe book metadata being available as linked data

Library Linked Data Dimensions / Topics

References (optional)