From the homepage:
A.nnotate is an online annotation, collaboration and indexing system for documents and images, supporting PDF, Word and other document formats. Instead of emailing different versions of a document back and forth you can now all comment on a single read-only copy online. Documents are displayed in high quality with fonts and layout just like the printed version. It is easy to use and runs in all common web browsers, with no software or plugins to install.
Hosted solutions are available for individuals and workgroups. For enterprise users the full system is available for local installation. Special discounts apply for educational use. A.nnotate technology can also be used to enhance existing document and content management systems with high quality online document viewing, annotation and collaboration facilities.
I suppose that is one way to solve the “index merging” problem.
Everyone use a common document.
Doesn’t help if a group starts with different copies of the same document.
Or if other indexes from other documents need to be merged with the present document.
Not to mention merging indexes/annotations separate from any particular document instance.
Still, a step away from the notion of a document as a static object.
Which is a good thing.
I first saw this in a tweet by Stian Danenbarger.