A popunder is an ad format that opens a full advertiser page in a new browser tab or window behind the page the user is looking at, so they see it only when they close or minimise the current window.
Definition
A popunder is an ad format that opens a full advertiser page in a new browser tab or window behind the page the user is looking at, so they see it only when they close or minimise the current window. A pop-up is the same idea in front of the current page.
"Clickunder" and "clickander" are related terms for formats triggered by a click anywhere on the host page. All of these deliver a full-page ad view with no creative to design — the offer's landing page is the ad.
Pop traffic is the cheapest and highest-volume paid format, priced on a low CPM, and it is entirely interruptive: the user did not choose to see it. That makes it low-intent, noisy and heavily filtered by ad blockers, but also abundant and inexpensive, so it survives as a testing and volume channel for offers that can convert cold, full-page traffic.
In context
For iGaming, pop traffic is used mainly for casino offers in low-cost markets and as a fast, cheap way to test a landing page or a prelander before committing to more expensive formats. Because there is no creative, the entire performance lever is the landing page itself: the first screen has to communicate the offer and a reason to act within the second or two before a user who did not ask for this closes the tab.
The quality and compliance profile is demanding. Pop inventory quality varies wildly, bot and accidental-click rates are high, and cohort analysis on deposits is essential because click and even registration numbers can look fine while producing no real players.
Pop is also close to the line on many ad networks and platforms, and using it to force gambling content on users who did not request it — or chaining pops and redirects — breaches policy. Licensed operators rarely use pop directly; it is more a grey-affiliate volume channel than a brand-marketing one.
Worked example
A buyer uses pop traffic to test three prelander variants for a casino offer at $0.90 CPM before running the winner on paid social. The pop test costs $200, identifies the prelander with the best click-to-registration rate, and the buyer moves that prelander to the more expensive format with a known baseline.
Related terms
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