The GNOME Foundation is hosting free web services.
As you probably already know, the GNOME Foundation is hosting Tomboy Online which is in an invite only alpha right now.
We also have a public instance of a Gobby server running, so you can edit documents real time with others by pointing Gobby at gobby.gnome.org! When we update to the new protocol, you will also be able to collaboratively edit in gedit. Gobby runs on Windows, Mac, Linux and other Unix like operating systems.
For those of you that easily host your own Gobby servers, this may not seem like a big deal. But for those of us that groan at the thought of figuring out how to host a server of any kind, keep it running and answer questions from others, well, this makes it a lot easier for us to use the free software services that are out there!