I'm pretty sure this question has come up more than just in the cfgb-referred thread above. Shouldn't this go into the site FAQ or something, cuz it seems that people are not doing their proverbial homework before asking this question.
Oops, snuck by me. We rolled all them zeroes over last night with a visit from our Russian friend YandexBot during the "mostly bots" hour. Closest users on either side were JustinShapiro (-16) and OndaGrande (+64).