Pop punk is a subgenre of punk played simplistically, but with good melodies. Lyrics have catchy hooks and are usually about love, alienaton, feeling insecure, or whatever the hell random thing the writer wants (
Da Stike by Millencolin is about bowling).
Unfortunately, the genre is being ruined by
MTV who are telling 14 year old girls that anyone who wears black and has emo-hair is punk. All of these bands are just posers who play watered down versions of the genre for personal gain.
Real
pop punk is real punk. In fact, in a way, is more punk than many others because they don't try too hard to be punk. Good
pop punk bands
will write songs that are the antidote for heartache. Bad
pop punk bands make heartache even worse (see emo)
Pop punk: Millencolin (personal fave), Screeching Weasel, Descendants, NOFX, Lagwagon, Rancid, Buzzcocks, Ramones, Blink 182 (Dude Ranch), Green Day (Kerplunk-Nimrod)
Not punk: Good Charlotte, Simple Plan,
Fall Out Boy, Yellowcard, All American Rejects, Sum 41 (even though I'll admit I like a couple of their songs)
Really really really really not
pop punk: Avril Lavigne