Facebook was founded by a small group of students at Harvard University and launched in 2004. It rapidly grew in popularity and now an incredible 500 million people from every corner of the globe are registered users. And Facebook is only the beginning: there's Bebo, MySpace, Twitter...Social networking has changed the way we flirt, fall in love, get dumped, take revenge, make and break friends, gossip and chat. It's little wonder that people are spending so long glued to their computers and smartphones.