Amy Editor 1.0
A Collaborative Text and Source Code Editor for Developers.
7 years old. 7 years unsupported, left behind as a relict. No warranty.
You may view the collaboration demo screencast to help you get started, even though the whole process is fairly simple.
One last thing: there's an Embedded Amy Demo available for those interested in wonderful editing capabilities within existing systems.
Thank you for visiting, have a nice day and enjoy! :-)