Slutty women in genral have lower self esteem..it shows. Some show it as a "high" sex drive, but you see it in their eyes. It is a "dead" look, and they hide behind the "sex drive", knowing that they only way that they can get a man close to them is thru sex. And many times it can be a pretty woman. Generally speaking most of the women on internet porn tend to be average or not model type pretty. So maybe there is a corrollation between attractiveness.
High school sluts are a lot diff than college or post college sluts. For instance, I had just started dating a girl in college that was quite high strung, and was average looking. And while I getting my haircut one day, a dude told me that she was slut, and it was a known fact. Well, what I didn't know was that she had been raped, and therefore tried to reclaim her sexuality by being "sexaully aggressive", ie, slutty. So as I said, there are many reasons for sluttiness, looks are just one aspect of it.