Inside Facebook security: defending users from spammers, hackers, and ‘likejackers’

If Facebook were a country, it would be the third largest in the world, just behind India and China. And like any country, Facebook has a police force to keep things under control. 300 people have been entrusted with the responsibility of keeping a 900-million-person virtual society from itself and from external forces. How do you look after people who use the same username and password on every website and get “hacked”? What about “likejackers” determined to make people spam themselves over and over again?