For the Twitter user who has everything: Qwitter, a service that notifies you by e-mail when someone unfollows you. The e-mail includes the name of the person who stopped following you and the text of the tweet that presumably made them do it. So you can either cry yourself to sleep over having said the wrong thing, or track down the unfollower and give them a hard time about it. Or both.

Someone please explain to me why I would ever want to use this.