BANNABLE: Do not ever expose an underage character to anything sexual. They must not have any knowledge or experience of anything sexual, or else the whole server could get shut down. No kissing, no nudity, nothing. As a correlate: do not bring underage characters into NewHome. Besides there being nudity there, it could confuse new players.
MUTE/WARNING-WORTHY: Do not discuss r*pe outside of a locked Place. This includes Banter, outposts, and unlocked rooms in Places. Absolutely do not joke about it! (It's not a joking matter!)
Similar to above: Keep really heavy topics (abuse, terminal illness, addiction, etc) to Places. They're not good Outpost topics. Though this is arguably a matter of taste, Outposts are public spaces, and it's not fair to blindside the general public with something that heavy.
Don't call the Bordello the Bordello (or the Dello) in public. This DOES include Banter! Instead, call it 'Byte's' or 'Byte's Place'.
Don't spoil the Stranger encounter. People can find spoilers if they want but don't talk about them! This includes Banter and outposts. (It's a stunning experience and it has the most punch if you go into it not knowing what you're in for!)