[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.]
All of Zynga's most popular games lost a huge amount of monthly active users on Facebook in the last two weeks, and Draw Something and Hidden Chronicles were the worst affected.
The Facebook app for Draw Something, which isn't an actual game but still connects to the mobile version of the Omgpop-developed title, has misplaced 2.6 million users somehow. And Hidden Chronicles now has 2.9 million fewer players.
CityVille, Texas HoldEm Poker, FarmVile, CastleVille, Words With Friends, Zynga Slingo, and Empires & Allies all lost at least anywhere from 1 million to 2.5 million monthly users in the last two weeks, and it's unclear why.
It's possible that many players of those games have migrated to Zynga's new platform separate from Facebook. Since launching in March, Zynga.com has picked up 2.8 million monthly players. Zynga's total user count on Facebook has dropped from 292 million two weeks ago to now 266 million.
Meanwhile audience numbers for other popular non-Zynga games -- such as Rovio's Angry Birds, King.com's Bubble Witch Saga, and Wooga's Diamond Dash -- have enjoyed growth.
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.