According to a report by AppData, leading Facebook publishers Zynga, Electronic Arts and Playdom saw declining numbers during December 2011. Zynga, the largest of the publishers by far, saw its daily active users (DAUs) were down 608,000 to 47 million.

Meanwhile, EA’s DAUs dropped by 1.2 million to 10.9 million over the month, with The Sims Social declining for the third consecutive month. Playdom owned by Disney also saw a drop of daily active users (448,000) to 3.1 million as Gardens of Time continued to lose users; the company has been criticized for not releasing new titles often enough.

DAUs for December 2011 (AppData)

It’s also worth noting that Zynga, who once owned over 50 percent of the social gaming market as recently as early 2010, now own an estimated 35.7 percent share. This change has mostly benefited the mid-level publishers, and the seven other companies that comprised the top ten saw their DAUs increase.

Tetris Online and Happy Elements the bigger increases during December 2011. Meanwhile, Wooga, King.com, GSN, Halfquest and Playtika continued to be more competitive and benefited from growth in secondary markets such as the Middle East.