bobasaur, i don't think anyone is forgetting that, it's just that for some people that's not the most relevant distinguishing factor.  :)  phantast thinks it's the artistic component that makes the difference, while you think it's the subject (its explicitness).  that's one more reason why i believe the distinction between erotica and porn isn't as useful as one might think at first glance, and why people will be arguing about it until the cows come home -- those definitions are along completely different axes, and they're not even the only definitions in existence.

phantast, when i say that art is in the eye of the beholder that isn't a snap judgment, it's a carefully considered one. yes, there is art theory and art criticism -- and have you noticed the immense disagreements within those over the centuries?  the arguments continue to this day:  should art teach us something about reality, should it be an articulate expression of the artist's emotions (ie. should it communicate), should it be harmonious -- and what constitutes harmony, should it be representational, should it be morally uplifting, does its true source lie in the mysterious (like religion), what about technical merit, does intent matter, does it indeed require a human creator at all (if it's carved by wind, can it be art)...

those discussions can be interesting and enlightening, and people who want to talk sensibly about art should know something about those questions.  but outside of that, when it comes to each of us here, and what we appreciate as art, it's personal.  i am decidedly unsure whether we can define art anymore.  it probably was easier before warhol, but i came to it afterwards  :).  there's value in the discussions for me, not in hammering down The Definition.

also, i find borderline conditions inherently more interesting, which is why i focus on them -- that doesn't imply a core doesn't exist (though truly, in this case i doubt whether one single core of art exists), it just says that i think that core gets plenty of attention as it is, and that borderliners get marginalized and invalidated by defendants of the core.  which is pretty much a given as soon as morality gets into the equation.