I'm more interested in seeing if there is something else out there. I haven't figured out why I haven't really found anything else I like so I'm asking what you like.
At risk of igniting controversy (or generating more heat than light), I might rank social media sites this way, from worst to best:
4Chan | Digg | Reddit | Slashdot | HN
Reasonable people may differ, of course. But I think there's little controversy over the idea that, when a site becomes popular, its quality necessarily declines -- unless there are barriers to membership.