Well, I have been playing with Facebook some lately. A friend of mine invited me a while back so I went ahead and signed up and added some friends. I have ran across some friends of mine and it's fun sometimes to see who I can run across out there. I am already on Linkedin and Myspace so we will see what Facebook has.
From what I can tell, you can't add java code to your profile so stuff like my Flickr badge and my Goodreads stuff won't work. I did find a Flickr replacement but it's not as good as the java badge.
Here are links to my profiles.