Does anyone know where I can find a compendium of online forums?

I hate to be the person who doesn’t trigger intellectual discussion, but I simply need help with this task:

A means of developing a list of the population of online discussion forums (general forums, not exclusively politics). Is there any sort of semi-comprehensive list out there akin to technorati.com?

Here are examples of forums so you can see what I mean:
http://www.ohiogamefishing.com/community/forumdisplay.php?f=5
http://www.carforums.org/