whiteboard looks actually quite good and the kind of thing i was looking for for our collaborativet writing;
the big brother versions look even better but are way to expensive.
i'm going to try it a bit more.
a big drawback for us (though would be a real advantage to some), is that it's a remote app hosted by them, which means we get locked into them pretty much once we start, and we don't have the kind of control to customize things that are possible when applications are run on our own server. i'd love to find an open source tool like this that i could install on the dc server.