Forums can be great, but even today most don't have the concept of "I've already seen this". That makes it hard to follow the latest discussions. The few that do have that concept are great, search them out.

Every time I logged into a forum, it would highlight all the unread posts. The latest post pushed the thread to the top. I'm not sure what forums you used that weren't like that. PHPBB and vBulletin both did that by default.

> but even today most don't have the concept of "I've already seen this".

Maybe I'm missing something obvious, but the way that normally works, is that you go to the last post you remember reading, then continue from there. So start at last page, go back until you remember what you're coming across, continue reading from there.

Probably only works for small/medium-sized forums though, the biggest forum I frequent only have ~20-40K users active and most (popular) threads die after 300-400 posts.

I used (and ran) phpBB-based forums back in 2007, and even then it would tell you which threads have new posts for you to see.