SCAM: It tweeted bad numbers, links and hastags under the test account. Stay away
This one was sent in and I was suspicious from the start called Followers Secret Monitor (1.01 beta). It appears for good reason. Using a test account I logged into the application with oAuth an gave it rights. I was expecting to see a list of who unfollowed me in some report fashion. Maybe by date or after what tweet.
Unfortunately what was shows was a screen with a very bad pull of the profile picture and a number of people that supposedly unfollowed the account. No times, no names, nothing. Except a button to find lists that will follow you back to grow your followers.
We have reviewed a tool like this before, but it read your current followers and then compared it to then show who stopped. I was unsure how this one could build the list without a start point anyway.
The site that runs this is TopTwitterShare which puts fun tweets on their homepage. So use this at your own risk to no result we have seen yet.