Enlarge Photo

Photo by: Paul Sakuma

** FILE ** This Dec. 13, 2011 file photo shows a sign at Facebook headquarters in Menlo Park, Calif. Facebook, the social network that changed "friend" from a noun to a verb, filed Wednesday, Feb. 1, 2012, to sell stock on the open market. Its debut is likely to be the most talked-about initial public offering since Google in 2004. (AP Photo/Paul Sakuma, file)

Happening Now