There's a reason phpbb went the way of the dinosaur and won't be making a comeback. The future is going to be something that learns from Reddit's mistakes without regressing to 2001 usability.
Having recently started participating in a community where most useful discussions are on a PhpBB forum, going back to linear posting was actually refreshing. It's easy to stay on top of because you can check in once a day or so and see just the conversations that have updates since you've last checked them. Threads being sorted by most recently updated means you focus on where there's active discussion. And once you've read those things there's no reason to stick around. "That's it! Get back to doing something useful."
Obviously, this doesn't really scale to a community the size of reddit, but I think it's really pleasant for medium-sized communities.
Here's the usability problem: You're 40 pages deep in a 100 page discussion and you see someone asked a question that you also want to know the answer to. How do you weed through the comments in the remaining 60 pages to find only answers to this question and relevant tangents? I've yet to see a conventional forum come up with a solution that doesn't involve a lot of friction or potential for missed information.
It is far too common for a forum's built in search tool to fail me for some reason or another, leading me to manually scan the entire thread. I may be willing to do that work if the information I am seeking is very important, but will I still feel that way if I just have a hunch that maybe I can provide my own input for someone else?
It might surprise you that, I think 4chan explores mixed threading like no other website does. Threads are linear, but quoting results in backlinks meaning isolated conversations are easily navigable, filtering out the "firehose". There's also a button that looks like [-] that can hide a post and all its nested replies, this can hide a specific reply chain from the linear view of the thread. I gave the system a bigger eulogy over here: https://news.ycombinator.com/item?id=33567593
https://en.wikipedia.org/wiki/Conversation_threading#/media/...
VS
https://preview.redd.it/r7k2gf1kav6z.png?auto=webp&s=9fd7a0b...
I think the flat sequential thread works fine with a limited number of messages. Eventually with enough replies it degrades to being very unwieldy like traditional forums.
In fact here's a screenshot from 2005
> It works reasonably well if users are careful to quote the messages they're responding to.
Unsurprisingly, they mostly weren't. Linear threads worked reasonably well when you were participating in or following a discussion as it unfolded; otherwise, they quickly became impenetrable.
I really liked how slashdot's threading defaulted to collapsing low-scoring replies down to one line with a short (expandable) excerpt of the reply. It really helped you take in the interesting parts without the fluff and snark hogging your screen.
my most beloved communities are still on phpbb. A "dinosaur" platform with a couple thousand tight knit members is way way more valuable than the nightmare we're seeing unfold with Reddit or any of the other social platform. When people prefer these platforms what they're really preferring is a high user count in their "community". Stable, quality, long term, online communities are better built off the major platforms.