Facebook has been going for so long that, when it started out, the term ‘social networking’ referred to meeting people, shaking their hands, and exchanging business cards. Now it’s all online; we poke, post and like–some of us even vine, tweet and instagram. Facebook began as a Harvard-based contacts directory. Today, it’s a global juggernaut of realtime, mostly accurate data from about one billion users. This is Big Data.