What is popunder? Therese Johnsen August 22, 2017 09:28 Updated Follow A popunder is a advertisment that opens a new window/tab behind the page you are viewing at the same time. Related articles Problems with adding a profile on chaturbate? What is CamHead? Where is the traffic comming from? How to pay with debit card using paypal with no account Camsites DivaTraffic works with Comments 0 comments Article is closed for comments.