Tom Wijsman asked: Some user (not necessarily low reputation) decides that he wants to put up inappropriate content (whether name, avatar, about me section or post). How would you determine if it goes over the line and how would you deal with the user in that case?
DragonLord answered: I'd start by sending a moderator message. If there's no response, the user will be suspended briefly. Whether the content is inappropriate would be based on the community's response.
Oliver Salzburg answered: I'd like to quote our faqfaq on that: "Treat others with the same respect you’d want them to treat you. We’re all here to learn together. Be tolerant of others who may not know everything you know. Bring your sense of humor."
soandos answered: The community has done a great job closing things as spam/offensive. No reason to interfere if not nessary. If it is, then I'll act as I imagine the community would do.
Daniel Beck answered: If it's something I consider universally offensive, I'll ask the user to remove it. Further action depends on the response. If I consider the offensiveness to be debatable (the recent XKCD issue is an example of this), actions depend on community response (e.g. others users flagging posts of the user referring to the profile or avatar).
KronoS answered: Jeff has stated that this site is supposed to be a clean environment. If I see anything of this sort, I'll address the user privately and encourage them to keep the site clean. Repeat and malicious individuals will be talked with other moderators, and possibly suspended