Forget about Google Docs and other online tools that promises to help you editing collectively your shared documents but doesn’t have a way to see the modification to the document in real time. Such applications are the past in collaboration tools: with EtherPad we have a really cool web-application to write plaintext with your friends seeing what others are doing live.
Here my 2 cents:
Why does EtherPad rocks?
You can see the modifications live. Do I have to add something more?
Try it and fall in love with its clean interface that provides nothing more than a shared Notepad. And does it well!
You can chat with your friends to talk about what are you writing and really collaborate on what you are doing.
What is still to be done?
Support for other document formats than plain-text should be great. Unfortunately the world is not only about simple text.
Also a way to store files on my disk would be appreciated. Or are you thinking in the Google-ish way that all my documents are belonging to you and only to you?
Please try to get a 100% availability :-D. This service is really cool but if I can’t talk with your servers is quite useless.
Thanks to Oscar for the link!