4th, really: Popular Digg, the version that drove people to Reddit (which they labeled as v4), whatever it languished as after that and before now where I think users could only comment, and the new site that just went live.
4th, really: Popular Digg, the version that drove people to Reddit (which they labeled as v4), whatever it languished as after that and before now where I think users could only comment, and the new site that just went live.