>which gives you just about everything a standalone forum could want except self-hosting.

A lot of forums want to not be joined at the hip with a cesspool of transient internet riff-raff which is exactly the problem that platforms that try to cater to everything (reddit, 4Chan) have. It's impossible to have real quality discussion about anything when the people who have deep interest in the subject are outnumbered 100:1 by people with passing interest.

It's an interesting trade-off... toxic subreddits exist, and hitting the front page instantly creates an Eternal September. BUT Reddit also gives you a suite of moderation tools out of the box. You can set rules, and benefit from site-wide policies that keep you on the right side of the law most of the time.

It's not perfect, but it's good enough that it seems to have won the segment by a fairly large margin.

The moderation tools are pretty poor once you start needing to do anything more advanced than banning users.

Reddit is a waste of time because threads get locked after a couple of months. (Sometimes, proper netiquette REQUIRES necroposting.)

Reddit has one missing feature in particular that’s important for some number of online communities: being able to include images in a comment.

RES kinda sorta helps with that in old.reddit.