Ad-tech
Popunder
A pop-style ad format — a new browser window opens behind the active one.
A popunder ad is a full-window ad that opens behind the user's active tab — they discover it when they close the parent window. PropellerAds, PopAds, Adsterra, and PopCash run massive popunder inventories. CPVs are low ($0.0003–$0.005) and intent is correspondingly weak. Best fits: sweeps, push-list builders, dating, mobile content. Compliance teams at Google/Meta consider popunders abusive and reject any LP that links to them.
Example
PropellerAds popunder buy at $0.0017 CPV sending US tier-1 mobile to a sweepstakes prelander. CTR-to-offer 12%, lead-CR 4%, EPC $0.014.