That's true, but there are other salient differences between Facebook and LessWrong. Like the fact the Facebook has a picture of your real face right there, incentivizing everyone to play nice, while we are hobbled with only aliases here. Or the absence of a nested discussion threading system on Facebook. Or the fact the Eliezer posts on Facebook all the time now and rarely here anymore. But I tend to agree that the aversiveness of karma drives people away.