I'd love a "go to first unread post" feature. Either the colored icon next to each thread title could serve that purpose, or when you hover in line with a thread title on the forum a button appears between the thread title and post count.
Regarding splitting the forums, at most I think creating an "off-topic" forum might be helpful, but I think splitting things too much could be more of a hindrance. This is a post I made some months ago
about doing something like "topic tags", in case people didn't want to split the main forum up.
I have an idea but am not sure how much work it would require. If GOG or forum members didn't want to separate the general discussion into subforums, what about creating topic tags?
General Discussion would remain the primary forum. When you create a topic, you would check a box marking the topic with one of the following tags: gaming, giveaway, or off-topic. You also wouldn't be able to press the "post my message" button when creating a new thread unless you mark a tag. This way every topic is appropriately marked under its respective sub-category.
On the forum page threads could have a different color for each tag (right now we have blue for announcements, yellow for questions, orange for sticky/FAQ). They could add a few more colors for the suggested tags (green for gaming, purple for giveaway, white for off-topic, for example).
In addition to this, the real suggestion I have is that on top of the forum page where you browse threads, people can check which topics they want to view. For example, if you don't want to read off-topic posts, you deselect that box and your general discussion page just shows gaming and giveaway topics. Or, you could save the URLs to each different list of threads if you want to browse them separately (instead of switching around between tags constantly). Something like: http://www.gog.com/forum/general
........(shows all threads OR the combination you've selected per your settings at the top of the page) http://www.gog.com/forum/general#gaming
.........(shows gaming threads only) http://www.gog.com/forum/general#giveaways
..........(shows giveaway threads only) http://www.gog.com/forum/general#offtopic
..........(shows off-topic threads only)
If the current forum infrastructure allows such a configuration, this could be a compromise between giving people an option to filter topics without actually splitting the forum up. I don't know how feasible or possible this is, though. It's just an idea so please don't hold my feet to the fire.
I fully support this idea. Tags are awesome! Easier for developers and for users. No need to code up specific pages, make a template and use tags to search. If the search functionality works, that is.