We're going to need a decentralized and censorship-resistant Internet/social media sooner than people think. By the next U.S. election, I fear the these three main sites will have already been co-opted to work as government propaganda arms [5], as a smooth transition from old TV media propaganda to Internet propaganda, as more people cut their cords.
The worst part is people won't even be able to easily see it. It's one thing to see a moderator on TV constantly hitting (or praising) a candidate and eventually realizing that maybe he or she isn't very fair or is biased, and may have ulterior motives for doing that.
But it's quite another to be so vigilant as to notice when Google shows you mostly pro-Clinton search results for neutral election-related queries, or when Facebook and Twitter "don't" allow some topics to trend (although I think more people are starting to catch on to these tactics, but it's probably not happening fast enough to make a difference this election).
[1] https://www.engadget.com/2016/09/14/facebook-twitter-first-d...
[2] http://observer.com/2016/09/facebook-and-youtube-show-franti...
[3] http://www.breitbart.com/tech/2016/09/11/hillary-health-stor...
[4] http://www.theverge.com/2016/9/15/12926058/facebook-dakota-p...
[5] https://theintercept.com/2016/09/07/google-program-to-deradi...
Somewhat relatedly, I tried following both the main Clinton and Trump subreddits for a while and there was significant value in doing so. They were often talking about entirely different shenanigans going down... but... they were so vitriolic (and, frankly, childish) that I had to unsubscribe to them.
So, there are standards of evidence, science and expertise, which the peanut gallery in politics has been hacking away at for decades, paid for by rich short-sighted oligarchs, esp for example oil (look at the anti-climate-science lobby).
Stuff like that + decentralized technologies would be great for social media, if we could get momentum behind it.
Propaganda by Jacques Ellul