Take the following with a grain of salt.
If it were easy to implement it would be great if there was a place on the forum where all of the new posts since a member last logged on were listed, irrespective of in which of the 29 categories those posts were made. Or, simply a chronological list (in reverse order) of all the posts.
I took the time to check, and there were 12 posts made today (Sunday 6 September), in 5 of the 29 categories. Only the latest post appears in the "Board Index" so, even if the latest post in those categories aren't of interest to someone, they still have to open each of the five, look if there are previous ones of interest, close the category, and repeat the process in the other four. If one of my suggestions in the first paragraph could be implemented, a person could easily skim through all of the recent posts to see what new of interest to them had been posted since their last visit.
Again, it's just a friendly suggestion. The forum is great, so the above in no way is meant as criticism.