I was reminded of this recently by Eliezer’s Less Wrong Progress Report. He mentioned how surprised he was that so many people were posting so much stuff on Less Wrong, when very few people had ever taken advantage of Overcoming Bias’ policy of accepting contributions if you emailed them to a moderator and the moderator approved. Apparently all us folk brimming with ideas for posts didn’t want to deal with the aggravation.
Avoiding trivial inconveniences that effectively discourage wider participation?
If that effect came as a surprise, it couldn’t have been the reason for the split.