[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.] There's been little movement on Facebook's App Leaderboard list for games lately -- the top seven titles on the chart are identical to the ones two weeks ago when we last checked in, though there are some fluctuations in their audience numbers. At the top, CityVille has 42 million monthly active users, down from 43.7 million two weeks ago. Texas HoldEm Poker managed to boost its numbers to 36.9 million from 35.8 million, and stayed ahead of Draw Something again. Draw Something's Facebook app, which isn't an actual game but is used by the mobile version of the Omgpop-developed title, is still growing and now has 36.3 million players compared to 33.2 million two weeks ago. Hidden Chronicles took #4 with 26.1 million users (down from 28.4 million), followed by FarmVille with 25.6 million (down from 27.4 million) and CastleVille with 25.2 million (down from 26.2 million). All of the titles mentioned so far are Zynga games. Rovio's Facebook version of Angry Birds is still growing and now has 23.1 million players, up from 20.8 million. King.com's Bubble Witch Saga inched up from #9 with 18.5 million players two weeks ago, to now #8 with 20.1 million. Making way for Bubble Witch Saga, Words With Friends dropped to #9 and went from 20.2 million users to 19.6 million. Diamond Dash from Wooga takes #10 and has 18.2 million players, a slight improvement from 18 million two weeks ago. Just outside of the top ten, Zygna Slingo jumped up a couple of spots and now has 17.6 million users (up from 14 million). This first licensed title for the social game giant has been performing well for Zynga, and was the fastest growing game last week. 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.