Advertising is a communication whose purpose is to inform potential customers about products and services and how to obtain and use them. Many advertisements are also designed to generate increased consumption of those products and services through the creation and reinforcement of a company's image and customer loyalty. For these purposes advertisements often contain both factual information and persuasive messages. Every major medium is used to deliver these messages, including: television, radio, movies, magazines, newspapers, video games, the Internet, and billboards. Advertising is often placed by an advertising agency on behalf of a company.

Advertisements can also be seen on the seats of grocery carts, on the walls of an airport walkway, on the sides of buses, heard in telephone hold messages and in-store public address systems. Advertisements are usually placed anywhere an audience can easily and/or frequently access visuals and/or audio and print.

Advertising spending has increased dramatically in recent years. In the United States alone in 2006, spending on advertising reached $155 billion. That same year, according to a report titled Global Entertainment and Media Outlook: 2006-2010 issued by global accounting firm PricewaterhouseCoopers, worldwide advertising spending was $385 billion.

Source: Wikipedia.org