Buzz in my gmail. It looks interesting; for me it has obvious benefits over Facebook. Facebook is such a time sink, all the crappy games that you are invited to play..
One of the things you can do is include my tweets from twitter, I expect that it is just a matter of time and my identi.ca tweets are included as well. This blogpost is an experiment as well; when posted it should appear as part of the buzz that I generate ...
In Google buzz you are connected to the people that you have contacted with by mail. This makes sense, what I still have to find out how I can include other people to follow.