Images. While "art" may be subjective, any image containing nudity which the poster considers art must be kept within the confines of the art forum, and marked as NSFW. While the art in question may contain nudity, it may not be sexual, or you will be banned. If you are unsure as to whether or not your image will get you banned, PM it to a staff member to have it cleared for posting. If you fail to do so and a staff member deems the image obscene, you will very likely be banned. If you post nudity (anything covered by a bathing suit) outside of a marked art forum thread, you will very likelyalso be banned. An image that implies sexual acts, regardless of whether or not it actually shows them, will also get you banned. Otherwise violent or disturbing images will be dealt with at the discretion of the staff, so use caution.
Bleys took the only rule that I feel was highly debatable so let's talk about everyone's other favourite subject: nudity!

Now I'm actually all for this rule. While I do think that society in general is far too uptight about things like sex and nudity and we should cast aside these puritan inhibitions and have crazy group sex parties left and right, the reality is that there's not only some underage users around (and the possibility of underage users exists), but also there's just not a whole lot of discussion value to be had about pictures of sex and nudity outside of an artistic context.

Now, we can certainly discuss the artistic merit, or lack thereof, of things like pornography, or discuss how terrible someone's boob job looks, or how big or small someone's penis is without pictures (ok, so maybe the last one is difficult without pictures), but is there any real value to it? Does such discussion really elevate the forum in anyway? Does it lend us any credibility as an FF news site? I'd say the answer is unequivocally no. Anyone disagree?

TLDR: you want to fap? Go somewhere else.