Two of my ex's played MMORPGs. They used to play (at least when I was with them) League of Legends and Dungeons and Dragons Online. Then one of my good friends plays Lord of the Rings Online, and a few friends play World of Warcraft of course lol.
I personally don't play, I kinda feel like I'd rather be skating or doing work in the library than playing an MMO... (then again, if Pottermore wound up being a MMO, I would have been all over that! lol)