I’ve used Google Docs in the past for some school assignments, and I must say it really sucks for collaboration in real-time. If more than two people are editing the same document at the same time, it turns into a living hell to keep the formatting in the document, and one editor from overlapping the other.
I then moved to Etherpad. While it lacks features, it works really great for plain text, which is what I use to share basic ideas, and a bit of bold for titles. And it would be a kick-ass online editor if merged with IDEone to run the code on the browser.
Now Google has acquired AppJet, Inc and they are supposed to work on Google Wave now, which is not what I really had in mind for them…