My impression is most iPhone users prefer using native apps or mobile optimized web sites. Who goes to cnn.com on an iPhone? They have a great app. I'd be surprised if FarmVille doesn't have an iPhone app -- probably coming soon if not. Porn? There's no m. porn sites? If not I just had a great idea for a new site...
I personally hate mobile version of sites. It presents a new interface where I have to find all over again the buttons I need. And sometimes those buttons are missing.