taxicab doors, roof mounts and passenger screens, musical stage shows, subway platforms and trains, elastic bands on disposable diapers, doors of bathroom stalls, stickers on apples in supermarkets, shopping cart handles (grabertising), the opening section of streaming audio and video, posters, and the backs of event tickets and supermarket receipts. Any situation in which an "identified" sponsor pays to deliver their message through a medium is advertising. Television Television advertising is one of the most expensive types of advertising; networks charge large amounts for commercial airtime during popular events. The annual Super Bowl football game in the United States is known as the most prominent advertising event on television – with an audience of over 108 million and studies showing that 50% of those only tuned in to see the advertisements. During the 2014 edition of this game, the average thirty-second ad cost US$4 million, and $8 million was charged for a 60-second spot. Virtual advertisements may be inserted into regular programming through computer graphics. It is typically inserted into otherwise blank backdrops or used to replace local billboards that are not relevant to the remote broadcast audience. Virtual billboards may be inserted into the background where none exist in real-life. This technique is especially used in televised sporting events. Virtual product placement is also possible. An infomercial is a long-format television commercial, typically five minutes or longer. The name blends the words "information" and "commercial". The main objective in an infomercial is to create an impulse purchase, so that the target sees the presentation and then immediately buys the product through the advertised toll-free telephone number or website. Infomercials describe and often demonstrate products, and commonly have testimonials from customers and industry professionals. Radio Radio advertisements are broadcast as radio waves to the air from a transmitter to an antenna and a thus to a receiving device. Airtime is purchased from a station or network in exchange for airing the commercials. While radio has the limitation of being restricted to sound, proponents of radio advertising often cite this as an advantage. Radio is an expanding medium that can be found on air, and also online. According to Arbitron, radio has approximately 241.6 million weekly listeners, or more than 93 percent of the U.S. population. Online Online advertising is a form of promotion that uses the Internet and World Wide Web for the expressed purpose of delivering marketing messages to