"Apps" are pieces of software that let Facebook's 500 million users play games or share common interests with one another. The Journal found that all of the 10 most popular apps on Facebook were transmitting users' IDs to outside companies. The apps, ranked by research company Inside Network Inc. (based on monthly users), include Zynga Game Network Inc.'s FarmVille, with 59 million users, and Texas HoldEm Poker and FrontierVille. Three of the top 10 apps, including FarmVille, also have been transmitting personal information about a user's friends to outside companies."
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