I met Kris and Maciej of netomat at Supernova and just got around to downloading and playing with the beta. It looks interesting. It's like an email/wiki/link sharing tool. It's written in Java and runs on Mac and Windows. It's pretty easy to use and is more "rich" than a wiki because it has things like drawing tools that let you annotate pages in a way similar to a white board. You create pages with your netomat client. You can publish it with editing enabled so anyone can modify it. It keeps a history of changes. You can email pages to people. You can include lots of things in pages including audio, images, links, etc.
If anyone else is running the beta, send me netomat mail so that we can mess around. I am jito on netomat. My first netomat page is here.