Correct, the information is available to that site. However, if that porn site were to turn around and say "On this date/time, the following IP address accessed my site and downloaded illegal photos of minors", and they were to give that information to a private individual without a warrant, that would be (as I understand it) wrong.

Isn't that what hundreds of american firms do whenever you access half the sites on the internet?

I never gave doubleclick.net permission to track my ip and all the sites i visit. But doubleclick do track that info and make it available.