Most discussion board software no longer offers a threaded mode, not even the hybrid mode which is great and a combination of both (which is the way I would go if you can find someone who offers it). But a caution on some of the new software such as vbulletin 5.2.3 which I believe is only the flat view. While they offer new features they seem to be unstable (though I do not manage any). I know some who do and I know they simple things such as using embedded links (a simple feature) can bog them down and lock them up. I have also seen one group that uses it have multiple crashes (though perhaps they have much more traffic than the Rams forum...in fact, they probably have factors of 10 more traffic so that may be the problem with them).

Earlier versions of vbulletin, such as 3.8.5 have the hybrid mode which combines flat and threaded (in fact, the user could pick which of the three modes they wanted to use) and that was the best, I don't know why they stopped offering it.

I have to say with regard to the flat view, having to scroll through scores of posts, maybe hundreds, is terrible. If there is a back and forth going on between two people it is almost impossible, sometimes having to scroll through and find posts on different pages. I have also found the search features on the newer software to be terrible (you think they would be better but that has definitely not been my experience). Some of those new features, perhaps most, are something that most people would never use IMHO.

I haven't had to work with one of these platforms in years, I'm speaking strictly as a user. I would say just make sure you know what you are getting and focus on the things you want to have the most rather than every little bell and whistle. But I don't like any flat mode but then I don't use my phone either. I don't know if you can purchase an older version of vbulletin with the choose your mode feature, including hybrid, but if you can, that is the choice I would make for what it's worth.