The first place I remember seeing it is Slashdot - so perhaps start there. It's weird how now it seems such a normal feature now despite the fact that in the p

The first place I remember seeing it is Slashdot - so perhaps start there. It's weird how now it seems such a normal feature now despite the fact that in the past even major forums like SomethingAwful and TOTSE (hell, that goes back to the BBS days..) had no such feature and functioned perfectly fine.