Reddit is a good example of how insane that can make discourse look in some subreddits, with one large one in particular showing how you truly can just engineer a faux consensus by deleting and banning every single comment and commenter that differs even slightly.
If we're going all in on how they've ruined their site, their change of the default sort to use a variety of engagement metrics rather than upvotes is why the frontpage is mostly ragebait and gossip posts, as those drive engagement metrics like comments, replies, and time spent reading comments.
There's also the fact that nearly 100% of frontpage posts are pruned by moderators within 12 hours now. Tracked by a subreddit (RedditMinusMods) that reddit banned without reason, but you can still find a link to a graph of that happening on HN of all places: https://news.ycombinator.com/item?id=36040282
