I've selected a bunch of forums in the "I never look at these so don't show them to me" section of the profile settings. It was working fine when I last logged on a few months ago, but today I notice it's ignoring those selections and showing me everything. Or at least a handful of stuff I told it not to--not 100% sure if it's hiding none or just a few.
A lot of new forums was created in the meantime. Perhaps some forums were shuffled around. Couldn't this be the reason?
Edit: when I go to the Java forum category, it shows all forums, even those I've chosen not to see. I believe this is the intended behavior - to be able to get to the forums one normally does not use. I'm not sure it was always this way, though.