hi and welcome to the site! :)
i have an account on aops, and I'm pretty sure there's a lot of ppl here who have an account there too since 90% of all questions on this forum are aops questions lol
I am enrolled in AoPS.
Loki, I must say, not exactly 90% but I definitely agree that there is a good 6-12% of AoPS.
And around 10% for the mathswatch ones.