Oh, by the way, 37 Signals' Writeboard is already out, and, yes, I think we'll all talk about it over the next 24 hours since it just opened up. I created one. Looks interesting, but I wish I could link off of my Whiteboard. That wasn't obvious. It looks like a dumbed down Wiki, to tell you the truth.
(Via Scobleizer: Microsoft Geek Blogger.)
I tried Writeboard too, and it just looks like a very simple collaboration tool with version control. I'll play with it a little more if I get time later.