Sneaky window

When I click to open the daily topic an ad window surreptitiously opens behind the main window so that when I close the main window the ad window is there.

This behavior verges on virus action. I assumed it was happening in facebook, and was disappointed to find it was happening on this site.

Not a virus or malware (though it could link to either) but a standard Ad tactic for less than reputable ad companies.

You can block these in a couple of ways.