German dog food maker Granatapet needed to introduce itself to pet owners with a slim budget, so came up with the idea of catching the target group while walking the dog, and using a “Pavlov’s dog” approach to condition the dog owners. The nascent brand’s campaign used “Check in!— Snack Out!” billboards with the social media app Foursquare to offer free food to dogs out walking with their masters. With a Foursquare check-in, the billboard released a pet food sample for the dog, which showed the owner how much their pet enjoyed the free offering.