A.nnotate lets users attach notes to precise places in the text of PDF, Word documents and web pages online. It is easy to use and operates in a web browser: the user simply highlights text and writes a note. All notes, documents and tags are added to their personal searchable index making it simple to get back to the right place. Uploaded documents are initially private, but can be shared by emailing a link. This lets several users comment on the same online copy of the document and add replies to each others notes. It acts like a shared online version of Word or PDF comments but avoids the usual problems of emailing documents back and forth and having to merge comments from different people.
Applications include peer review of research papers, indexing documents and web pages, web research and collaboration on writing new documents. It is also being used for content curation and populating scientific databases. Curators tag words or phrases in articles which are then used to create database and index entries. The advantage is that claims in the database are then backed up by references to the precise source and context in the literature.