Phantom Lord Said it best:
"They need not be XXX hardcore to be porn."
Which is the point when you get down to it. Who gets to draw the line? You? Me? Phantom Lord?
You have to be super careful with arguments like this because many people I know would call your images pornographic, explicit, and eeeeeevil. Want them to police your house? Read your email? (Porn can be written too.)
I don't.
Hell, people in the past and too this day consider such great works as David to be porn because you can see his whoo-whoo-dilly
I would say, there is certainly a difference between porn and erotica. Porn, to me, involves overt sexual acts. Erotica is more subtle- Vargas pinups from WWII are certainly erotica, but they aren't pornographic.