Slashdot, Digg, Reddit, HN.
On a two year or so schedule new ones come along, old ones become worse. People on here are already using those illiterate, infantile 'memes' to express themselves. The next step is HN gone wild.
The only question is, where do I go next? I'm not going to pretend it's going to have than two years to live though.
/. has gone entirely to shit, but some subreddits are still good (it feels like the average user age has been suppressed down about seven years, though).
The problem is the revenue model. You can't be exclusive when you need to cater to as many users as possible.