Lyrical resonance isn't necessarily indicative of emo though - I mean I agree with everything you say about writing lyrics on yr pencilcase &c (which I did as a teenager!), but eg just because Cassie's lyrics resonate with me on an emotional level does not mean that Cassie is emo.

And while I don't deny that angst is big for teenagers I'm not convinced that overt angst (rather than angst sublimated beneath macho fronting or pop platitudes) is so dominant - the equivalent would be imagining everyone in my year at school being into Tori Amos and Courtney Love. (Although having said that all the boys did seem to like Nirvana.)

(Of course emo is dominant among teenagers on livejournal though!)