Etherpad was a great idea, online simultaneous editing. After the team was acquired into Google Wave they dumped what they had in open source, and moved on. A few brave souls tried to improve it, but it was a beast, and seems to have died on the vine.
Fortunately a few new brave souls have decided to try to build a conceptual fork from the ashes of etherpad. The new version is written in node.js (all the hipness now), and called etherpad-lite. The install isn’t too bad, and I’ve gotten a couple instances up and running so far.
Etherpad has become a critical tool to me for coordinating distributed teams. We use etherpads as part of remote planning sessions. While it’s not quite the same as a whiteboard, it’s closer than you’d imagine, and the fact that everyone has a cursor makes it easy for anyone to speak up and make changes. The most important part of a plan is that everyone that’s part of it buys into it, and participation is one of the best ways to ensure that happens.