Emma Pierson writing about tweets and Ferguson notes that red and blue tweeters live in discourse environments that are nearly fully separated. The graphic produced by her demonstrates the severity of this division.
So we have two groups of people who rarely communicate, have very different backgrounds, think drastically different things, and often spray vitriol at each other when they do talk. Previous studies of Twitter have found similar echo chambers, the Israel-Palestine conflict offering one representative example. It is unclear to what extent Twitter merely reflects social divisions as opposed to causing them; I find it unlikely that Mckesson and the red tweeters would be friends if they met over beers. But even this preliminary analysis does not bode well for the possibility of reconciliation.– from Quartz (post)
That said, it’s not clear that the intent here is to communicate to each other. As Bonnie Stewart and others have noted, these events are used by activists tactically, and the goal is not persuasion of enemies but often the much more narrow aim of shaming the press into covering an undercovered story, alerting other activists of an event or issue, or mobilizing moderates into to more radical action.
Bonnie Stewart talks about the activist uses of Twitter. See Tactical Twitter
Related to polarization: in social media, Anger Spreads Fastest
Our world now is a result of the lifestream concept. See Lifestream History