My highschool only did prom king/queens.
You voted for couples throughout a certain time in the year, the top 3 got picked and you voted out of the 3.
Somehow, I got nominated, and somehow won.
I honestly was never really extremely popular, a lot of people knew me because I was really involved in theatre and other activities, and I just tried to be nice to everyone. I was well known and well liked I suppose, but not your typical 'prom queen'
I was by NO means the most attractive girl in my year, I'm 3 years out of highschol and still have NO idea how I managed to win.
(I think it was because of my DBF who I must say, was definitely the most attractive guy in our year, and I think whoever would've been with him at the time would've won queen to his king.)
Some schools in my area to prom king/queen by random draw--which I personally think is a TERRIBLE idea, because then kids who don't even know each other have to do the first dance sort of thing, AND it risks having kids be traumatized/made fun of (like the thread you're referring to)
I don't understand the whole point of prom king/queen to be honest.

I don't think winning prom queen in my graduating year really did anything for me (positive or negative) I don't think I'd be any different if I hadn't won. I do know that a lot of the more popular "mean girls" at my school did have a major hate-on for me afterwards though.
