Are we doing Forums the wrong way?

[WiBu]

I'm going to keep this short and sweet (and open ended) as I wouldn't want my opinions to sway any discussion right off of the bat.

However, I've been thinking recently about how forums are designed from a user perspective. For the most part they're highly segmented, things being tucked away in separate categories, it doesn't really promote exploration or spontaneous discussion. Why is it like this? Could we do better?

Obviously, I have my own ideas, but as said in the opening, I'll save them for later.