A thumbs up or «Like» icon at the Facebook

A thumbs up or «Like» icon at the Facebook main campus in Menlo Park, California, May 15, 2012. Facebook, the world’s most popular internet social network, expects to raise USD $12.1 billion in what will be Silicon Valley’s largest-ever initial public offering (IPO) later this week. AFP PHOTO / ROBYN BECK (Photo credit should read ROBYN BECK/AFP/GettyImages)