a half billion, and the average person spends 27 hours on facebook each month. the problem, keeping it in a world where hackers have targeted some very high profile brand names. for the people who work at facebook, october is a sort of test to security team sets up simulated attacks, then gauges how employees react and learn from the hack. >> this is the hack. >> they call it hackt o rks ber, a focus on traps by fake news stories, e-mails, or web links and stopping an attack before it starts. but what should the rest of us be watching for? security pros say if a message from a friend or something on his or her wall looks suspicious, flag it. >> sometimes, something seems out of the ordinary, it probably is. and so, it's a great thing to sit there and think, you know, so and say wouldn't say that, and that's something that's