- Associated Press - Thursday, May 17, 2012

Growth in the number of active users at Facebook, defined as someone who logs on at least once a month:

1 million _ End of 2004.

5.5 million _ End of 2005.

12 million _ End of 2006.

20 million _ April 2007.

50 million _ October 2007.

100 million _ August 2008.

150 million _ January 2009.

175 million _ February 2009.

200 million _ April 2009.

250 million _ July 2009.

300 million _ September 2009.

350 million _ End of 2009.

400 million _ February 2010.

500 million _ July 2010.

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