Facebook Blocks Some Apps in an Attempt to Reduce Spam

In the past week, Facebook has shut down a number of third-party software applications on its site, including a new poker app and Breakup Notifier, which lets users know when certain friends become single.

Facebook's move is part of an effort to reduce mass emails to its users and to more closely monitor apps running on its site, InformationWeek reported.

The Breakup Notifier developers are working to restore the application, which a Facebook spokesperson confirmed is only temporarily disabled, according to InformationWeek.

Facebook is the world's most popular social network, last month attracting 153 million unique visitors. That also makes it the fourth most popular U.S. Web site after sites owned by Yahoo (YHOO), Google (GOOG) and Microsoft (MSFT), according to research firm ComScore.