I started developing a popup script with a link back to the opening page around 1998. It has gone through several stages of refinements. At first, it opened an html web page in the little popup window, but as server speeds improved, the popup web page loaded too late to capture the opener's address. To cure this, the MR function opens the popup and writes the html code immediately into the popup, so the link back is accurate. When I set up my Google AdSense account, I carefully read the TOS and interpreted it to allow use of Magic Return. I configured MR to open if the mouse was over the ad when the page unloaded (not when the ad was clicked, which would be a violation of TOS.) There were quite a few emails between me and AdSense support, and I tried to make a case for my position that MR should be allowed, but, in the end, Google ruled that using MR would be a violation of TOS. Anyway, you can use Magic Return with ad servers that are not so nitpicky, or just when you are linking to pages outside of your website,