"CityVille now has over 100 million active users..."
Now I believe there's a big difference between that figure and those individuals who are running multiple accounts. There's some lady at work here who's daughter has TWENTY-TWO different Farmville accounts. And another lady that has SIXTEEN of her own. I don't play these dumb games, but I understand having multiple accounts makes it handy to give gifts and collectibles to other accounts.
I mean we're still talking in the tens of millions, but if having multiple accounts is the norm for these players, than that 100 million figure could actually be half or less of actual individual players playing the game.
Although I think it's absolutely retarded to "play" these games, you have to hand it to Zynga for tapping into this non-traditional "gaming" crowd to make billions.
To develop something that has 100 million users (probably ~65-70 million if you take into account the multiple user accounts) is still very impressive, regardless of what you think of the game. Chances are another game like this is going to come out in the next 12 months with even more users.