Out of Pod Experience

I've given legal advice to a couple of friends from another MMO. And one of them referred an RL friend of his to me, and that turned into actual "business," i.e. a case with a paying client.

One of these same two friends is an amateur fiction writer. I proofread/critiqued the drafts of his chapters as he went along, and the book ended up getting published. Now he's semi-pro, and he runs his drafts by me for critiques.

Another MMO friend and I came close to purchasing the game from the owners. (It was an ancient, mostly text-based MMO that they were hardly maintaining anymore, so pretty cheap). We had the investment cash and the little business plan all lined up, but the game's owners decided not to sell in the end. (Once we showed some interest in buying it, they got all fired up about it again...!)

So I'd say it's possible for MMO friendships to cross over into RL collaboration or business.