Burger King sold a penny Whopper to people inside McDonald's

By 2018 Burger King's mobile app lagged far behind McDonald's and other fast-food rivals in downloads and daily use, despite years of ordinary in-app coupons and push notifications. McDonald's had roughly 14,000 US locations to Burger King's much smaller US footprint — a real-estate disadvantage no discount inside Burger King's own app could offset.

The agency's insight inverted the problem: McDonald's larger footprint wasn't just a competitive threat, it was free geographic coverage nobody else could match. If the app could turn proximity to a McDonald's into the trigger for a Burger King offer, Burger King's ad would appear exactly where its rival's foot traffic already was.

The app used geofencing to detect anyone within 600 feet of one of 14,000 McDonald's locations, unlocked a one-cent Whopper offer only there, and turn-by-turn routed them to the nearest Burger King to redeem it — turning a competitor's own real estate into Burger King's ad space.

Geofenced mcdonald's to unlock a penny whopper only nearby, then routed users to the nearest burger king, turning the rival's real estate into free ad space.

Geofencing McDonald's locations ensured the offer reached only people already considering fast food.

The absurdity of luring customers away from a rival generated earned media, amplifying reach.

The stunt drove app downloads and awareness, though not a large sales lift, showing its narrow power.

Turn a rival's strength into your trigger: use their footprint as free targeting data for your offer.

1.5 million app downloads in nine days, made it the #1 app in Apple's App Store, and — per Adweek — a reported 37-to-1 return on investment with 3.5 billion earned-media impressions. Burger King's overall U.S. comparable sales rose a modest 0.8% that year, per Marketing Dive; the campaign's clearest impact is in app installs and earned media, not overall same-store sales.