Here is a twitter based service called Qwitter (http://useqwitter.com) which tracks your followers on Twitter and alerts you every time a follower quits following you.

Not only that but it also show you the message after which the follower quit. So that you know where you went wrong if at all you did.

All you have to do is, just enter your Twitter ID and the e-mail address to receive alerts. The way this service is setup you can actually follow anyone you want to, but I don’t see a reason anyone would do that.

Also, the service does not restrict twitter ID’s to be followed more than once. For example, you can register to follow tnerd on Qwitter that does not mean I cannot register to follow tnerd again.

Click here to visit Qwitter.