Yeah, I don't know who they are. Watching the trades scroll by, I occasionally see some that are over 100 BTC. I just saw one for 228 BTC @ $225. Somebody dropped $53,500 on bitcoins. I don't know who has that kind of money, but Voorhees suggested that venture capitalists (and perhaps investment firms) are climbing on board. I read somewhere that a MtGox employee revealed that their ticker API gets hits from known IP addresses at investment firms, banks, and governments. So, there's clearly interest in those groups.