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Every other week, Gamasutra examines the fastest-growing Facebook games according to monthly active users, looking at which titles and developers are having the most success attracting new players on the social network.]
Zynga's latest release and its first game from the popular hidden object casual gaming genre,
Hidden Chronicles, is the fastest growing game on Facebook this week, picking up around 8 million users. Since its launch three weeks ago, the game has received 9.5 million players.
The developer calls
Hidden Chronicles "the most social hidden object game available," and enlisted the help of Cara Ely (creator of popular hidden object series
Dream Day Wedding) and Jane Jensen (creator of the acclaimed
Gabriel Knight adventure games) to craft the title.
Words With Friends, another Zynga title, is the second-fastest growing game on the social network after adding 1.2 million users for an 18.3 million total. After that, there's Zynga's
Texas HoldEm Poker, which welcomed 1 million new card players for a 31.1 million total.
King.com's
Bust-a-Move/Puzzle Bobble clone Bubble Witch Saga has 600,000 new users and an 11.9 million total. Another puzzle game, Tetris Online's
Tetris Battle, a social game adaptation of the seminal title, also has 600,000 new users and an 11.9 million total.
Empires & Allies (14.6 million total) by Zynga is at #6 with 400,000 new players, tied with Halfquest's Arabic game
Happy Farm (5.1 million total). Electronic Arts' newly launched adaptation of Hasbro's board game,
RISK: Factions (550,00 total), recruited 370,000 users.
Candy Dash (710,000 total) and
Diamond Dash (13 million total) both gained 300,000 users -- despite their similar titles, they're not related.
Candy Dash is a new and cute-looking puzzler from Brazilian developer Vostu, while
Diamond Dash is a puzzler from Germany's Wooga.
The full list of the top 20 fastest growing Facebook games along with exact monthly active user counts, are as follows:

All charts and data are courtesy of Facebook application metrics and trends site
AppData.