So people regularly use (in casual conversation, in fiction, etc) music as markers of personality and character — the sort of music that sort of person would listen to, listening to that sort of music carries *these* connotations. Music, basically, as cultural signifiers, as cultural coloring.
ASIDE: Personally, I happen to think a lot of this is bullshit (which is perhaps affected by the somewhat separate fact that I think it would be a better world if everyone recognized it as bullshit); I happen to think that a lot of what degree it isn't bullshit is actually about tribe/class/etc rather than personality (and sometimes rather damagingly conflates the latter with the former).
But set those personal beliefs aside: the fact is people do it, and do it a lot. My problem is that I simply don't know these associations. I was just listening to a podcast where someone said "I couldn't put U2 on that playlist" and another person said "thank you", and they clearly had the same association with U2 and I don't have the slightest fucking clue what it is. (My only association with U2, beyond knowing a few of their songs, is that when I was in Ireland several decades ago there was a huge amount of basically nationalistic love for them. That wasn't what these podcast people meant, though.) What did U2 mean in that sentence (aside from the specific band, which is only a fraction of what it really meant)? I genuinely don't know; I can guess a bit from context, but not very specifically, not very richly, not very accurately. (I know a tiny bit of it for classical and jazz. But only a bit. And that's not what gets most used, by a very long shot.)
ASIDE: Actually, these things are so vague that I rather suspect that people themselves have very different understandings of them: that one person will say, "U2, damn" and another will reply "I know" and that they'll never work out that they are actually meaning almost entirely different things.
It seems to me, however, that this is precisely the sort of thing that the web ought to help with. To tell us not only who U2 is (members names, song names, release dates) but what they mean — or, more accurately, what they are taken to mean, including any big disagreements in that. I'm thinking of something vaguely like "urban dictionary", except for bands/singers/songs. Except I don't know of anything like that. It's certainly not on wikipedia (probably too opinionated, although it's the sort of thing I wish wikipedia had more of, frankly).
So: does this exist? And if not, can someone build it? (And please don't say 'you do it!'; obviously, I am the *last* person who should try this, or I wouldn't be asking.)