Collaborative Writing Tools
From Robin Good at 
Collaborative Writing Tools are "technologies that facilitate the editing and reviewing of a text document by multiple individuals either in real-time or asynchronously.
Online, web-based collaborative writing tools offer great flexibility and usefulness in learning groups and educational settings as they provide an easy means to generate text exercises, research reports and other writing assignments in a full collaborative fashion.
Collaborative writing tools can vary a great deal and can range from the simplicity of wiki system to more advanced systems. Basic features include the typical formatting and editing facilities of a standard word processor with the addition of live chat, live markup and annotation, co-editing, version tracking and more.
Documents generated with such tools are always accessible to all the editors and can be easily downloaded and exported in standard word processing file formats."
Mini-Guide by Robin Good at http://www.kolabora.com/news/2007/03/01/collaborative_writing_tools_and_technology.htm