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Every other week, we examine 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.]
Zynga's biggest games, some of the most popular apps on Facebook, continue to lose monthly users -- in just the past two weeks,
CityVille at #1 had its population drop by 1.9 million to 79 million. Keep in mind that earlier this year, that number crossed the 100 million mark.
Empires & Allies, the newest Zynga release on the chart, has cooled since its rapid ascent to #2. The turn-based strategy game lost around 390,000 users since mid-July.
FarmVille is even more worse off, shedding 2.1 milion virtual farmers and now at 34.9 million players.
Texas HoldEm Poker at #4 wasn't safe either, as it folded around a million players in the last 14 days, holding onto 34 million. Gaia Online's
Monster Galaxy fell from #6 to #8 this week, and dropped a third of its audience (5.7 million users), now sitting at 10.6 million.
Playdom/Disney's
Gardens of Time actually gained users, though only about half a million for 16 million players, as it climbed a spot to #5.
FrontierVille (12.1 million) and
Cafe World (11 million) from Zynga follow, after losing 1.3 million users and 500,000 players, respectively.
And at the end of the top ten chart for Facebook's most popular games, there's PopCap's
Bejeweled Blitz at #9 (-320,000 users, now at 10.5 million), and Wooga's
Diamond Dash at #10 (-362,000 users, now at 9.9 million).
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.