This is really a subject that's impossible to define. What's erotic and what's pornographic really depends on individual's belief and background. In US, there is no clear definition of what is pornographic. Even in legal sense, what's allowed and what is not allowed is vaguely and ambiguously defined and usually determined on case-by-case basis. APUG is an international community where member spans every part of the globe. Trying to define what's acceptable from progressive Europe to traditional Arabic countries, and confused US is simply not possible. More interestingly.... use of pornographic material is typically the highest in more traditional part of the country. (in US) How do I know any of these? I am currently studying human sexuality at a college. So all this did not come from you know where.
If someone wanted to start a controversy, this is probably the best topic.