Things I think should be treaded upon carefully if not avoided altogether:
A lot of this is material which is well accepted at LW.
Humor is commonly upvoted. It's possible that you have a different concept than I do, and mean something specific by jokes. There's a certain kind of hostile humor which may be more trouble than it's worth, but if so, we're going to need to be a lot clearer about what it is.
I'm not sure how much explicit talk about sex there's been here (as distinct from, say, talk about orientation or polyamory), but I don't think a discussion of how to improve sexual experiences would be out of place.
I personally wis...
For example, what would be inappropriately off topic to post to LessWrong discussion about?
I couldn't find an answer in the FAQ. (Perhaps it'd be worth adding one.) The closest I could find was this:
However "rationality" can be interpreted broadly enough that rational discussion of anything would count, and my experience reading LW is compatible with this interpretation being applied by posters. Indeed my experience seems to suggest that practically everything is on topic; political discussion of certain sorts is frowned upon, but not due to being off topic. People often post about things far removed from the topics of interest. And some of these topics are very broad: it seems that a lot of material about self-improvement is acceptable, for instance.