Web annotation

A web annotation is an online annotation associated with a web resource, typically a web page. With a Web annotation system, a user can add, modify or remove information from a Web resource without modifying the resource itself. The annotations can be thought of as a layer on top of the existing resource, and this annotation layer is usually visible to other users who share the same annotation system. In such cases, the web annotation tool is a type of social software tool. For Web-based text annotation systems, see Text annotation.

Web annotation can be used for the following purposes:

Annotations can be considered an additional layer with respect to comments. Comments are published by the same publisher who hosts the original document. Annotations are added on top of that, but may eventually become comments which, in turn, may be integrated in a further version of the document itself.

The W3C has a Web Annotation Working Group which has issued 3 Recommendations:

The W3C also had a previous web annotation standardisation effort, Annotea (see below), which was conceived of as part of the semantic web.

Many of these systems require software to be installed to enable some or all of the features below. This fact is only noted in footnotes if the software that is required is additional software provided by a third party.

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