Glossary
Clickunder
A script that opens the advertiser's page in a new tab on the user's first click anywhere on the publisher's page. The same traffic as popunder with a different trigger; sold per thousand by pop networks.
Also called: click-under.
The publisher's page looks normal; the first click on anything also opens your page underneath. The user finds it later. Networks bundle clickunder with popunder as pop traffic, and buyers treat them the same: cheap, huge, bot-prone, good for smartlinks and sweepstakes.
Both formats are banned by browsers where they can be detected and by platforms that care about experience; they persist on sites that do not.