It took over 200 years for the population of Australia to reach 22 million. It's taken CityVille, the latest game from Farmville creators Zynga, just eleven days.
That's right. Twenty-two million in eleven days. While detractors of this type of casual Facebook gaming can point to the fact most of those players haven't paid a cent, and that it's a lot easier to get 22 million signed up to a browser game than to go out and buy a "real" one, that doesn't diminish the scale of 22 million players.
CityVille is basically SimCity for the microtransaction Facebook crowd. You can read more about it here.