Fake Follower Check is an online service dedicated to checking your Twitter followers to see if they are real or fake. Fake Follower checks how many spam accounts are following you.
Fake Follower will take a sample of your follower data which can be up to 1000 records depending on how popular your account is. For example simple check conducted by Fake Follower will be to check a user account for its followers and accounts its following. Most of the spam/fake users will have heavy counts in the followers (which he/she is following) list but hardly even 1 follows them back.