well….they are hurting you….they are stealing your content and making it there own. you see when you click on your page in the frame, the web address stays on there web address.
they are stealing your traffic….although what i think is stupid is, if someone clicks on an aff link on your site…you get the credit not them….so they are doing it for malicious reasons only….to steal rank.
but by putting that code on your pages, it makes your real site come up with web address and all….
IMHO….I am by no means an expert on these things…. :wink-wink