When you opened up this page, you might have experienced another window opening in the background, with advertising material on it. This is because the page here has some code that is malicious. I have no idea where this came from, I have tried deleting all extra tools and code that I can and reverting the page to the basics, but the popunder, as it is called, remains.
Often, such code is hidden within javascript, which accesses a remote location which is where the advertising is posted.
So, I apologise for any inconvenience, and request that you bear in mind the advertisers who are using this method, because they deserve to never gain by doing it. Casino websites, for instance - could you trust them to be fair in gaming when they cheat even to advertise? What about products? Would you buy from a car dealer who has cheated to get you to attend the showroom?
I think not.