Anyhow, my original design for the forum included this feature but then I decided it would be better not to fix something that wasn't broken yet. As you said, there are pros and cons to dividing up the forums into categories. I doubt having a forum for each appliance would improve the user experience. More choices aren't always a good think. Sometimes simplicity trumps over that.

But... adding optional tags per post might be a nice way to achieve something similar without the cons. It's on my todo list to take a closer look at sometime.