At the time I had that idea I got the impression that some of the people around me were leaning too heavily on what I was calling the "epistemic lens," where your perspective on people is primarily based on their beliefs. I think this is mostly unhelpful, e.g. it can cause people to be snooty about religion for what I see to be no good reason. I think an "instrumental lens," where your perspective on people is primarily based on their actions, is much more helpful. In general I'm a fan of instrumental rationality, rather than epistemic rationality, being the more foundational thing.
I suggested recently that part of the problem with with LW was a lock of discussion posts which was caused by people not thinking of much to post about.
When I ask myself "what might be a good topic for a post?", my mind goes blank, but surely not everything that's worth saying that's related to rationality has been said.
So, is there something at the back of your mind which might be interesting? A topic which got some discussion in an open thread that could be worth pursuing?
If you've found anything which helps you generate useable ideas, please comment about it-- or possibly write a post on the subject.