Youtube: Censors youtubers, documented in so many cases. It also gives "authoritarian news" a heavier weight in the algorithm. Removes comments with "communist bandits" in Chinese.
Twitter: Seriously bans people if they say the wrong pronoun
Reddit: A few people controls the majority of big subreddits, bans people with conservative views outright. Bans people that upvote stuff that they don't like. The have removed, banned hundreds of subreddits and users in the last few months. While they have chinese owners.
Facebook: Surprisingly the best of the bunch when it comes to serving every viewpoint imo. But they have had huge privacy implications just so many times.
But even so, I am very torn on the subject. The best thing would probably to force these companies not to censor/ban/remove people based on opinions. But the best thing for the world would most likely for these social media sites to not exist in the first place.
Personally I think social media sucks but I think most people are not ready to live without it either.
But, yeah. There's a lot of people that would be better off not on social media. But it's so addictive that they can't help themselves.
I, for one, have stopped using social media (unless you consider HN social). And I've had a lot less friends because of it. But it's been a huge improvement in my mood and outlook on life.
On HN, it's a lot tougher to follow specific people, though it's cool to see posts and then follow up with what they've recently posted or commented.
But the dynamic is definitely different and seems a lot more anonymous unless you are a really high profile account like antirez, patio11, drewdevault, or a CEO of some well known company or startup.
* Broad reach - they are accessible to and used by a population broadly for public communication rather than a specific subset of the population or private communication.
* Optimized for engagement - Content is personalized and optimized for individual engagement. Compare this to a stream of content organized by time (email inbox) or basically time with minimal voting/decaying (HN)
* Feedback is quantifiable and visible - Likes, retweets, upvotes (ie, engagement metrics) are countable and displayed to users. I think this gets at something deep in the human psyche and encourages users to chase those metrics.
It turns out that in systems with all three (FB, Twitter), you create enormous echo chambers that only occasionally flare up into outrage when they inevitably leak to a broader audience. This is great for engagement but pretty self evidently bad for society.
Lots of sites fit somewhere on this spectrum (including HN and Stack Exchange) but have basic safeguards to prevent the worst types of behavior. But this is usually because they aren't profit motivated to slide all the way to one side on the three factors above.
I don't want to be dismissive, if you have some kind of distinction you're trying to get at, I'm open to hearing it. But I personally don't see a big conceptual difference between Reddit and a forum, other than that one of them happened to get bigger. And I'm pretty skeptical of using size as a criteria here, because it would force us to say that Google+ and MySpace stopped being social media at some point when they dipped in popularity.