How's your Twitter Karma?
If you still do your following by hand, you might find that there are plenty of people you follow who don't follow you, and vice versa. But there's no easy way to figure out who falls into which category on Twitter. And that's where Twitter Karma comes in. It's a third party tool that analyzes your Twitter account and brings up a list of users you follow, users who follow you, and makes it easy to see whether you have a reciprocal or one way relationship with each.
You'll need to give Twitter Karma your username and password to let it do its stuff. But the same can be said for most Twitter desktop applications, so you're always taking a leap of faith when you decide to trust anybody that's not Twitter with your login information.