Facebook has taken on more responsibility for your social life than you might think. I think most people assume they are seeing most of what their friends say, but they aren't, as a recent Daily Beast investigation showed.
The service takes all your friends and decides, based on a secret ranking system, which of the things they say should show up in your News Feed. Because that feed is the default way that most people see stuff on Facebook, that algorithm has become the de facto social filter for hundreds of millions of people. Even if you would never consciously consider using an algorithm to shape your friendships -- surprise! -- you already do.
And yet we don't know much about how Facebook's system actually works. So, the Daily Beast, led by editor Thomas Weber, devised a simple and interesting experiment. They got a Facebook newbie to sign up and twelve volunteers to friend him. When he updated his status or shared a link, they watched their own feeds to see if his posts showed up. Often, they didn't. It helped if he shared a link. And it helped a lot if he shared a photo or video. But those little, "Heading to the grocery store" tidbits? They were heading out into cybernothingness.