Actually, I stole that from James Carville, proving that he knows his business. ;P
Anyway, LiveJournal has this little feature called "friendsfriends," where you can view all of your friends' friends lists, sans any mutual ones you may have. To see it, all you do is go to your friends list and add "friends" to the end of the URL. Thus, my friends page is http://the-gneech.livejournal.com/friends, and my friendsfriends page is http://the-gneech.livejournal.com/friendsfriends.
I pop on there every once in a while out of curiosity or to find interesting communities; today I was quite discouraged to find that apparently almost all of my friends' friends are political rants from either the right or the left, with all the pointless chaff you would expect from same. Some are communities, some are simply individual posters, but all are repeating the same malarkey you can easily find on any talk radio show, newspaper op-ed, or other source of punditry.
I did find a Sinfest RSS feed, tho, so it wasn't a total disappointment. :)