MixedInk is a free collaborative writing tool. MixedInk takes a fresh approach to collaborative writing. It's a fun, democratic and elegant way for people to weave their best ideas together. (Plus, it's free!)  

• MixedInk Blog
• Video demo
• How to Use this Site
• Examples
  • Netroots Political Platform
• Article
  • Netroots Share Words to Reach Consensus