The term "pay per call" is sometimes confused with click-to-call, the technology that enables the "pay-per-call" business model. Call-tracking technology allows creation of a bridge between online and offline advertising. Click-to-call is a service which lets users click a button or link and immediately speak with a customer service representative. The call can either be carried over VoIP, or the customer may request an immediate call back by entering their phone number. One significant benefit to click-to-call providers is that it allows companies to monitor when online visitors change from the website to a phone sales channel.