This one strikes a chord with me, being a Kuro5hin expat. Here's a discussion among k5 users who have come to see the community as a walled garden and realize how the centralized architecture of the site limits the use they can make of it.

"Right now, we're all constrained by K5 mechanisms and K5 borders. K5 is the AOL of the blogging world."

As I wrote a while ago, "rigidity and tight coupling is going to be a hindrance to the growth of communities like k5 in the long term. Intelligence and freedom need to be at the ends, not at the center." As the tools available to individual users progressively become more widespread, easy to use and powerful, I'm tempted to predict an erosion of community diaries by independent blogs, and wouldn't be surprised to see a similar effect at work between centralized (i.e. Ryze, Friendster) and decentralized (i.e. FOAF) online social networking architectures.