Annotation is now a web standard

While many applications, from PDF readers and Google Docs to the Kindle, support some kind of annotation functionality, what the W3C formalized yesterday is fundamentally different. The W3C architecture provides for a model where annotations live separately from documents and are reunited and reanchored in real-time whenever the relevant document is present. The benefit of this is that annotations now come under the control and election of the user, rather than at the sole discretion of the publisher.

Whereas previously annotation was likely a solitary act when implemented in a native app, or the most public act when it took place in a Disqus or Livefyre comment widget, web annotations will allow users to form communities freely, and those communities can extend across any internet-connected document, whether in HTML, PDF, EPUB, or other formats.