Before we get too far of track here, let me say that as far as I know, this is simply a matter of framing our site in a small frame from another site.
While I'm only speculating on this, I believe the reason to do this is to take credit for ad clicks or views, or otherwise claim the traffic. I have been to a few sites that will refer you to other sites and trap you in their frame; not having any patience with it I killed it and didn't look further. I believe some of the domain-camping "search" sites do this kind of thing as well; if they can get you to bookmark their page instead of the page you actually want, they get traffic credit.
They aren't stealing anything by using the content. The credits and site titles all appear. This is no different commercially than you selling me a book, which I then put in a gift box and resell at a profit. If they are claiming our ad revenue, that's theft.