95% of it is shit. It takes the old pop genre, and shits it down a drain. This kind of "music" is aimed at the target audiences of teens and kids who don't appreciate other kinds of musics.
To a mainstream pop fan, anything that contains yelling or screaming is for emos who "cry in teh corner whill we give boys a head".
If you hear mainstream pop being played, destroy the device playing it and you'll save your sanity.
Justin Bieber - All of his songs
Lady Gaga - Again, all of her songs,
Jonas Brothers - Wannabe "rock" stars who plays pop "rock". Has NOTHING to do with actual rock or alternative rock.
ALL of those are mainstream pop