Most healthy intellectual blogs/forums participate in conversations among larger communities of blogs and forums. Rather than just "preaching to a choir" of readers, such blogs often quote and respond to posts on other blogs. Such responses sometimes support, and sometimes criticize, but either way can contribute to a healthy conversation.
If folks at Less Wrong saw themselves as a part of a larger community of rationalists, they would realize that most rationalist authors and readers are not at Less Wrong. To participate in a healthy conversation among the wider community of rationalists, they would often respond to posts at other sites, and expect other sites to respond often to them. In contrast, an insular group defined by something other than its rationality would be internally focused, rarely participating in such larger conversations.
Today at Overcoming Bias I respond to a post by Eliezer here at Less Wrong. Though I post occasionally here at Less Wrong, I will continue to post primarily at Overcoming Bias. I consider myself part of a larger rationalist community, and will continue to riff off relevant posts here and elsewhere. I hope you will continue to see me as a part of your relevant world.
I worry a little that Less Wrong karma score incentives may encourage an inward focus, since karma is so far only scored for internal site activity.
As a regular reader of overcomingbias.com (through RSS) I honestly had never really noticed lesswrong.com yet, until Eliezer repeatedly posted about it recently. I do remember talk about reducing the number of posts on overcomingbias.
Overcomingbias.com is wonderful, because it is unique, perhaps, and because the contributors have lots of interesting stuff to say. Apart from that and in spite of the unambiguous title, it`s identity doesn't seem overly clear. It doesn't always seem overly focused on actually, practically overcoming bias.
That's perhaps where lesswrong has a role to play: as an exercise by an actual community in overcoming biases, being less wrong, in "real life". For now though it isn't clear to me yet where this new site is headed. The people involved are obviously interested in the same issue that are discussed on overcomingbias, especially those of the Eliezer variety, so is my first impression.