[Every other week, Gamasutra examines the most popular Facebook games (according to monthly active users), looking at the top titles and developers on the social network to see who's attracting or losing players.] On the games leaderboard this week, Zynga one again has the top spot with CityVille. The Sim City-style social game has 75.4 million monthly users, not much less than the 75.7 million it had two weeks ago when we last checked the most popular games list. Two more Zynga titles, Empires & Allies and Texas HoldEm Poker take the next two spots -- the former strategy title has 39.9 million users (down from 42.6 million), while the latter card game has remained steady at 36.6 million virtual card players. #4 is where the list gets interesting, as The Sims Social, which formally launched a month ago, jumped to that spot after overtaking Zynga's FarmVille audience numbers. Based on the long-running Sims franchise, The Electronic Arts/Playfish title now has 36 million monthly users. The Sims Social also now has more daily active users at nearly 9.5 million compared to FarmVille's 8.2 million. By that measure, it's second only to CityVille, which launched in December and currently has almost 13.7 million daily players. That doesn't mean Zynga's titles are any less popular on the social network, though, as FarmVille is still sitting at #5 with an impressive 36.8 million users (up from 34 million), followed by FrontierVille successor Pioneer Trail with 22.2 million users (up from 18.7 million). Disney and Playdom's Gardens of Time comes in #7 with 17.1 million (up from 17 million). After that, we have Zynga's Words With Friends with 13.2 million (up from 10.8 million) and Wooga's Diamond Dash with 11.5 million (up from 10.4 million). And Cafe World, yet another Zynga game, closes out the top ten list at #10 with 10.2 million users (down from 10.3 million). In the top ten, Zynga obviously continues to dominate, taking seven spots. You can see the full list of the top 20 Facebook games along with exact monthly active user counts below: All charts and data are courtesy of Facebook application metrics and trends site AppData.