Here's a new application (that I got wind of from the Pharma Strategy blog) called mirror.me that analyzes your Tweets and assembles a word cloud describing your Tweet contents/interests.
I can't resist such arcane features and especially if I can focus this on myself. So my Cloud is on the above link. If you click on individual words, you can see users in my community with similar interests.
You can create your own cloud when you get to the site and have some fun.