#1 Twellow
Twellow allow users to browse other twitters based on their interests. Twellow only allows users to put themselves into 10 categories which prevents people from stuffing themselves in every category in a sad attempt to get followers. The site itself could use a redesign, but it’s a great tool.

#2 Twitterholic

TwitterHolic shows users their rank by the number of followers they have and how they rank based on where they live. It also has a line graph showing how many followers a specific user has had in the past and how many are predicted for the user in he future.

#3 TwitterFox

Twitter fox is a cool Firefox addon that lets you Twitter and keep things moving.