Facebook's Like button is a built-in filter bubble

Imagine if every newspaper came with a mandatory T-shirt. Suddenly, that tabloid you paged through out of curiosity becomes part of your identity. You have to explain to friends that despite being a walking billboard, you don’t actually agree with The Wall Street Journal’s conservative editorials, or think The New York Times is too liberal but still covers the facts. Increasingly, you stick to outlets you unambiguously approve of, reinforcing things you already believe.
This is how F