An interesting discussion of the effects of communication technology on political polarization includes this nugget
Although technology has contributed to polarization, it may also help rescue us. For example, Facebook has automated story selection for its custom news feed; for political news this tends to foster an echo-chamber effect. However, Facebook data scientists have found a better source of diversity: almost 30 percent of hard-news reports originating from friends reflect opposing views. Even better, individuals are likelier to engage with information like this when it is presented in a social context.
I found this especially interesting because our surveys show that Facebook is by far the most common source of information at the bottom of the pyramid in our part of the world.