Collaboration on genealogical matters has been an abiding interest of mine for the last three years. Having just come across the WeRelate site yesterday (1/13/2007), it feels like a huge burden has been lifted! Now I don't have to create the mechanism for doing the collaboration - and I get lots of help with content, as well.
This is such a cool site; I've looked at lots of others, but nothing compares.
Now, I can spend more time getting to know my ancestors (and the context in which they lived) and less time trying to track them down!