A genre of rock started in the 70s and lasted through the 80s. There are still some punk bands now, but they are very scarce.
The media tries to tell you that punk is listening to My Chemical Romance or dressing in all black, etc. However, true punks dress according to their whim and listen to whatever they want.
Emo kids are just pseudo-punks. Don't let them convince you that they are individuals, because emo is the mainstream trend of 2005. True punk has no set style or gimmick.
REAL punk rock: Dead Kennedys, Ramones, Rancid.
FAKE punk rock: Blink 182, Good Charlotte, Green Day.