A record label specializes in manufacturing, distributing and promoting audio and video recordings, on various formats.
Major record labels don't care about putting out 'great music'. They only care about making money. That's why they normally focus on signing artists who are eye candy (ie good looks, sexy, good dance moves, dresses nice etc..)
Even though most record labels are out of touch with what most music fans want, they convince their artists that they are in touch with what music fans want. That's why most artists end up being hated by the same music fans who used to love them.
Record labels love to prey on naive artists (who don't know a lot about the music business) because they're easier to milk for everything that they're worth.
Record labels (and their middlemen)usually bribe radio stations to play their artist's songs (i.e. payola).
Most record labels are very corrupt.
If you sign with a major record label without knowing anything about the music business, you're gonna get screwed.
Sometimes it's better to sign with an "independent" record label.