Suggestions

@Rowdy

OH shoot like just colouring the visited links? Sorry, shows how much I've been thinking in PHP lately :')

I use multiple devices, so that'd just end up being irritating to me (since whether it displayed as visited or not would be dependent on if I'd clicked on the thread on that specific device, as well as on having not recently cleared my browsing history - so I would very frequently see threads I'd already visited displayed as unvisited.) I would want it to be optional in that case.

I agree with the web-dev, who has written something above me.
It would actually not be that much work to realize the concept.
Thumbs up from me!

_{this got buried but i want more people to see it. it would be so useful!}