If you've ever been unfollowed on Twitter and wanted to know why, Qwitter is the Twitter service for you. Almost as elegant at Twitter itself, Qwitter simply asks you for your email address and twitter username, and then the service watches your Twitter follower list and sends you an email when one of your followers stops following you - including the last tweet you posted before they "qwit."

Although there are other services which track usage like this, Qwitter is, as of this writing, the only one that attempts to tell you why - although there's no guarantee that it was your latest tweet that broke the camel's back.

With pundits lining up on both sides of the Qwitter fence, one thing is certain - the proliferation of services like Qwitter shows that users and developers are continually seeking to build upon and expand Twitter's no-nonsense, pared-down interface - and that the much-buzzed Bay Area social network may have a lot to learn from its user base.