Farmville, a game most "serious" gamers shun, has something like 62 million players. In contrast, last I heard World of Warcraft has about 12 million. At this point hardcore games seem like they've become the niche. Arguably it's already happened. The Wii, in my opinion, marks the moment when the sea change occurred. A lot of people wrote the Wii off as a gimmick, but I think they missed the point: It wasn't popular because it was gimmicky, it was popular because the sort of games that were on there appealed to people that the game industry had largely been ignoring. Games like Wii Sports or Wii Fit have a much broader appeal to people who aren't traditionally gamers than dual-stick shooters.
From what I've heard, it sounds like the average player of Farmville is 43 year old women. (I don't have hard sources to back this up, but I don't have reason to doubt what I've heard either.) No wonder it's been so huge -- how many other games can you think of that appeal to 43 year old women?
People are saying "social games are huge now", which is true, but I think it also misses the point. It's not just about social games, it's about games that are accessible and inviting to people who normally are intimidated by games.
