At the moment when most social networks flatline, Facebook is taking off. But for Mark Zuckerberg, 175 million users are just the beginning of his headaches. Money, spam, and crime are spoiling his online utopia.

Mark Zuckerberg, the 24-year-old CEO of Facebook, wants to know what everyone in the world is feeling. But did he really want to get inside the head of 19-year-old murderer Leon Craig Ramsden?