Phpbb is almost unreadable for me. What he's missing is persistently collapsible comments.

Say for example in this discussion someone mentioned internationalization which I don't care about with 50 replies. I collapse this comment and it's 50 children and this discussion is for me still very readable. It must be persistent because if I return in 30 minutes I don't want to collapse same posts over and over. I also collapse posts that I have read and I'm not interested in replies. This effectively makes me a moderator.

Subreddits protects website from off-topic posts. Nested collapsible comments protects posts from off-topic comments and tangents.