I've mentioned previously that it would be helpful if Twitter users received better feedback on unfollow requests. Basically, let people know when their followers are dropping so they can at least know that they're burning people out, pissing them off, or underdeliverying in some other way.

Well, now you can do with with Qwitter. After signing up with the service, you'll receive an email alert every time you lose a follower. In addition, it will send along a copy of the last tweet you sent before being unfollowed, which may give you an indication of what it is that you said that generated the unfollow request.

The last post may not be the final straw, but I doubt many people lose followers based on a single tweet. More likely, the follower wasn't getting the type of content they were expecting for a while and they just happened to be near a computer (where it's easier to unfollow) at the time.

Personally, I think this is a great new feature that should help improve the quality of Twitter over time. A little negative feedback can go a long ways.

As far as positive feedback goes, check out Favrd, where you can track the "most favorited" tweets on Twitter.