The mysterious occurence of when a fan of a band starts to suddenly hate said band as soon as they become popular, appear on MTV, and are heard on the radio. Often, a fall out fan will insist that the band was ruined by mtv, when, in reality, the band has not changed at all except for their popularity status. Usually is in response to all the new teeny bopper fans. Named so for the band Fall Out Boy, which has many fall out fans.
Teeny Bopper: omg did u see (insert band name here) on mtv last nite??? they were lyk pwning!!111
Fall Out Fan: They were only good before mtv TOTALLY RUINED THEM.
by Katinthehat May 2, 2007
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These people are either real fans or fake fans.

A real fan usually has been a fan for a long time, and likes other bands similar to them such as P!ATD, Green Day, My Chemical Romance, etc. and likes songs other than songs from the Save Rock and Roll album.

A fake fan usually is a fan of mainstream/pop music and discovered Fall Out Boy from the radio, when it played "My Songs Know What You Did In The Dark (Light Em' Up). That is basically the only song they know. They label the band as emo, even though they are clearly not.
Fall Out Boy Fan:

Fake Fan: <3 omgggg I luv da Fall Out Boys! Light Em' Up is my fav songgg!!! Oh and I think his name is Pete Stump but he is rally hoooottttt <3333 I am like sooo über emoooo!!! lol I'm so hardcoreeee ^_^

Real Fan: I fucking love Fall Out Boy. Joe is my favorite because of his cool Afro! From Under The Cork Tree is such a cool album, but Save Rock and Roll was ok, I was expecting more tho. I miss Patrick's sideburns and Pete's guy liner +_+. And if you label them as emo, you die.
by Pseudonyms Suck May 24, 2013
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