Collabedit – Collaborative Text Editor
http://collabedit.com/

Collabedit lets several people work on the same document, at the same time. All changes are instantly applied to everyone’s screen. Collabedit provides a productive way to take collaborative notes, observe coding sessions, get help drafting emails and more. It works in your browser, no sign up required. Features include: a) document history (new), b) chat, c) changes appear in real-time, and d) syntax highlighting for programming languages. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.