What is interesting, is that you can tag people friends or foes. When you friend someone, suddenly you can see icons appear on other accounts: friends-of-friend (green/red pill), and foes-of-friend (green/green pill).
I never got the impression that the tagging system is widely used, however.
I try to address this with completely transparent and public voting, and also non-numerical voting, meaning every vote has to also be a "tag", like on Slashdot: insightful, interesting, troll, flamebait, offtopic, etc.
But not only that, you also get to see who tagged you, and this tells you whether it's someone you know or just some random.