Neil Harris said:
Great! If we have both Nicholas and Tony in agreement on this, we have the beginnings of a consensus. Possibly we need different tags for {{artistic nudity}} and {{hardcore porn}}, and we can argue on the nuances that lie inbetween? Let's develop some tag classes, and then get tagging! Then we can worry about what we do with the tag information later.
I don't think we should have a "hardcore porn" category, on the grounds that pornography usually means material with no other meaningful purpose than to sexually stimulate the viewer, and this purpose is not consistent with Wikipedia's goals. "Photographic depictions of sex acts", "Line drawings of sex acts", etc, would probably be the right category for most material that, if viewed outside the context of an encyclopedia, would tend to be pornographic. "Artistic nudity" is a bit too general--the term has been used to describe cheesecake and posed erotica that has no artistic merit. Again I'd be inclined to stick to clinical descriptions rather than risk opening the debate on artistic merit. Thus Leonardo's famous Vitruvian Man (currently one of the inmates of the "images containing nudity" category) would be in "line drawings where genitals are visible" or something.