Advertising is paid and/or sometimes free communication through medium in which the sponsor is identified and the message is controlled. Variations include publicity, public relations, product placement, sponsorship, underwriting, and sales promotion. Every major medium is used to deliver these messages, including: television, radio, movies, magazines, newspapers, the Internet, and billboards. 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 PA systems. Advertisements are usually placed anywhere an audience can easily and/or frequently access visuals and/or audio, especially on clothing.
Advertising clients are predominantly, but not exclusively, for-profit corporations seeking to increase demand for their products or services. Some organisations that frequently spend large sums of money on advertising but do not strictly sell a product or service to the general public include: political parties, interest groups, religion-supporting organisations, and militaries looking for new recruits. Additionally, some non-profit organizations are not typical advertising clients and rely upon free channels, such as public service announcements. For instance, a well-known exception to the use of commercial advertisements is Krispy Kreme doughnuts which relies on word-of-mouth.
The advertising industry is large and growing. In the United States alone in 2005, spending on advertising reached $144.32 billion, reported TNS Media Intelligence. 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. The accounting firm's report projected worldwide advertisement spending to exceed half-a-trillion dollars by 2010.
Source: http://en.wikipedia.org/wiki/advertising
