On February 23, W3C, the standards body for the Web, standardized annotation.
“Many websites already allow comments, but current […] systems rely on unique, usually proprietary technologies chosen and provided by publishers. Notes cannot be shared easily across the Web and comments about a Web page can only be saved and viewed via a single website. Readers cannot select their own tools, choose their own service providers or bring their own communities.”
What does this mean?
The W3C standards are a key milestone towards a future in which all pages could support rich layers of conversation without requiring any action by their publishers—because that capability can be built into the browser itself and be available as a native feature, just like web search. The shared vision is that conversations will be able happen anywhere on the Web, or even on documents in native apps, and inline instead of below-the fold, in a federated, standards-based way.