There are quite a few Twitter tools and services out there, one I have found recently and is quite interesting is Twittersheep.

What Twittersheep does is create a Wordle style word map based on the biographical description of your followers.

It’s a kind of one off Twitter service, but what it does is indicate the sort of people you follow, as you can see from mine, learning and e-learning are included in a lot of my followers’ biographical descriptions.