I think people just lost interest, mixture of the community losing interest and the founder losing interest. The rise of blogs didn't help, I don't think: many of the people who in 1999-2004 would've written an article to submit to Kuro5hin would today prefer to post it on their own blog and just submit links to places like HN/Reddit. That has the advantage of letting you "own" your writing, to build a personal brand, perhaps monetize it, etc.; but it does result imo in a bit less of a community aspect.

K5 was interesting to me, and I actually was the one who negotiated an ad deal between Andover and Rusty to help him with money for the first couple years. K5 had very much the same feel as Everything2 which was the "other" site to Slashdot that the original krewe did. E2 still has a tight community with numerous marriages, people still talking. I think the problem with K5 is that become too self-referential, and ultimately people lost interest. That was the same thing with E2 -- while people for a time loved being part of the community at some point you have to start to do other things in life and the time commitment drops away.

The day it dawned on me that the way you pronounced k5 was "corrosion" my mind was blown.

metafilter is the closest thing i've seen to k5 in terms of the kind of writing the community encouraged

I once had something I wrote on the front page... that was crazy. Remember how you would submit a post for editing first, and let the grammar geeks fix every little thing first? And you didn't just post a link to a blog post, you wrote the whole thing right there, on the site, the longer the better. I just looked for a link, but apparently my stories are too old, and are gone, and my last diary post was 2004. Anyone know where you can go to find that kind of community nowadays?