Guys are very visually based creatures. We're wired that way. And we're not very good with descriptions. That's generally why a guy can name something like 10 colours, (Black, white, yellow, green, brown, blue, pink, grey, orange, purple) whereas a woman can name and distinguish something like 115.
So we can't say :
"Look at Kathy over there... here oblong face doesn't quite suit her features, does it? Not with hair like that."
"Indeed, and the vaguely asymmetrical features are a little off putting"
"Killer t*ts though."
No, you're much more likely to hear "See your one over there?"
I don't get it either. I don't do it and neither do any of my guy friends. I have a female friend who does... apparently I'm an 8, but I could be a 9 if I tried? whatever... my rating system is yes or no. (would you go out with her?). I think the whole 1-10 rating system is completely subjective anyway, one guy's 10 might be another guy's 7 and yet another guy's 5... bootom line its not important enough to worry about, so don't. :)
They find it fun I guess. I've never rated anyone and never heard any guys talking about it.
Why do women gossip about everything? Guys rate girls because we like looking at them, and like to find/see attractive ones before the other guys, the whole purpose isn't would we date her, it's just a bit of fun and most guys are discrete about it and have codes, not just yell out 'Shes a 7'
I don't know why so many people do that. I don't think most people do, it is just that you hear the ones doing it, but you can't hear people not rating others. Of the ones that do, I think it has more to do with male bonding, by talking about our shared interests. Most guys do like talking about pretty girls after all.