U2 is a great band, its just most people on these forums are into harder rock.
To anyone who says Tool never sold, out, you're dead wrong. Having 3 songs on Guitar Hero, AND creating a venue. That's pretty sell outish to me.
Emo is short for emotive hardcore, and emotive hardcore was a movement that came to light over a decade before these modern bands. They actually played a cohesive strand of music, and the scene was fairly good. So that's the difference.