Some people fear that social media creates an echo chamber in which we only hear opinions from like-minded friends which confirm our own.
Eytan Bakshy, a researcher at Facebook, conducted a fine, huge experiment. Facebook normally shows you links that your friends have posted. Using a modest sample of 253 million users, Bakshy suppressed some of that sharing, to create an experimental and a control group. He wanted to see how much people shared links, whether they shared links that were kept from them but that they found some other way, and whether they shared more from their strong-tie or weak-tie friends.
If Facebook were an echo chamber, we would mostly be sharing links from friends and from strong ties more than weak.
What Bakshy found is that we do share links from our close friends. And we do share links that we would have gotten from our close friends - Bakshy hid them, but we found them anyway. So far, so echo-y. But we also share links from our weak ties, ones we would not have seen otherwise. And the number of links we get and share from weak ties overwhelm the number we get from close ties. Weak ties bring us novel information.
My experience confirms this finding. I share opinions with close friends every day on Facebook. But I also get contrary information all the time. Some comes from a few close friends who do not agree with me. But most comes from weak ties - acquaintances who are "friends" but not really close friends. Even more often, people I do not know contribute comments to a friends' post disagreeing with that friend. Almost daily I find myself reading and checking a contrasting idea that someone I sort-of know put on Facebook.
This keeps me honest. Good for busting the echo chamber.