The boundary between erotic art and porn is indeed a contentious one, particularly when some artists go out of their way to confront what many would find disturbing. I tend to draw the line in such a way as to include as art what a lot of others would not like at all. In response to this thread, I've had a look at the "Hot 20" (which I never did before) and ... yup, it's cheap porn. What is it doing on Renderosity?