Pay-per-call (also called cost-per-call) is an advertising model in which advertiser are charged for valid phone calls.  Although the advertising model has been around for decades in DRTV, radio, and print advertising, the growth of smartphones has reintroduced the phone call as an extremely viable means of generating leads and new business. Pay-per-call is an extremely powerful advertising model for local businesses and to clients whose customers wish to talk to the seller before buying a product such as insurance carriers.