Twitter sends an email notification mentioning so-and-so-person [with their tweets, followers, etc info] is following me, the moment someone follows me.
But Twitter does not send any email after someone unfollows me. Is it possible to know when someone unfollows me on Twitter?
I use http://goodbyebuddy.com/. Works well, with a nice responsive UI
There are a few services and bots out there that perform this function, but the easiest to use appear to be Qwitter and TwUnfollow.
Another site, basically doing the same thing: Who Unfollowed Me
The downside to all of these sites: they only track your unfollowers from the moment you sign up with the site, so there is no way (as far as I know, and I've been looking ;) to find out who unfollowed you in the past.
