To get large groups of people to dance, there needs to be something accessible about the music. The beat can't be too esoteric, but unless we're talking about prog or etherealist composition, I think there's something simplistic about most music. What's completely insane to me is that people would consider music that's simple to be dumbed-down. Couldn't simplicity be a deliberate, smart choice? Those people aren't really listening; they're judging a song off of a beat, off of a pulse.