This thread makes an interesting read to see different views of CSers on this subject. (Hey, I didn't know some of these models are porn-stars in their own right!)
My humble opinion is that we should respect diversity and respect what others do - be it the photographer or the model. This world is getting to complex for anything to be labelled black or white...or whatever degrees of grey shade (for you guys doing most b&w photography!). Seriously, if you think it is porn, it is; if you think it's not, it will be not. As long as nobody puts any degratory pics or illegal ones here, it's just fine.
We are at the stage of human development now that we can see more things in a faster way thanks to the Internet. Sometimes, certain things that we see seem to go against our moral grounds. But if you look to the ancient past, things are not much better or worse than now.
I do not have the guts to take such photos, so my respect goes to the photographers and models. Do I like them? Not necessarily. Do I object to such a subject? Sure, especially now that I have kids. But my views on this does not mean that I will exert them on others who does not share views as mine. We may have to agree to be in disagreement.
Finally, life is all about CHOICE. If you don't like anything, just look/go away.
p/s: This is my 100th CS post...and I love CS!