study on itself. Farhad Manjoo has some details,
"The new Facebook study is one of the largest and most rigorous investigations into how people receive and react to news. It was led by Eytan Bakshy, who began the work in 2010 when he was finishing his Ph.D. in information studies at the University of Michigan...he found that the closer you are with a friend on Facebook—the more times you comment on one another’s posts, the more times you appear in photos together, etc.—the greater your likelihood of sharing that person’s links. At first blush, that sounds like a confirmation of the echo chamber: We’re more likely to echo our closest friends.
Although we’re more likely to share information from our close friends, we still share stuff from our weak ties—and the links from those weak ties are the most novel links on the network. Those links from our weak ties, that is, are most likely to point to information that you would not have shared if you hadn’t seen it on Facebook."
What does this all mean? It means that through your network you are not just exposed to news and ideas that you could have found on your own or agree with based on your own world view. Its seems, on first impression, that the echo chamber does not exist.