In popular usage, "marketing" is the promotion of products, especially advertising and branding. However, in professional usage the term has a wider meaning of the practice and science of trading. The American Marketing Association (AMA) states, "Marketing is an organizational function and a set of processes for creating, communicating and delivering value to customers and for managing customer relationships in ways that benefit the organization and its stakeholders."

Marketing practice tends to be seen as a creative industry, which includes advertising, distribution and selling. It is also concerned with anticipating the customers' future needs and wants, which are often discovered through market research.

The scientific study of marketing is a wide and heavily interconnected subject with extensive academic publications. Marketing methods are also informed by many of the social sciences, particularly psychology, sociology, and economics. Anthropology is also a small, but growing influence. Market research underpins these activities. Through advertising, it is also related to many of the creative arts. The marketing literature is also infamous for re-inventing itself and its vocabulary according to the times and the culture.

Internet search technology to serve advertisements based on website content, the user's geographical location, and other factors. Those wanting to advertise with Google's targeted advertisement system may enroll through AdWords. AdSense has become a popular method of placing advertising on a website because the advertisements are less intrusive than most banners, and the content of the advertisements is often relevant to the website.

Currently, AdSense uses JavaScript code to incorporate the advertisements into a participating website. If the advertisements are included on a website that has not yet been crawled by the Mediabot, AdSense will temporarily display advertisements for charitable causes, also known as public service announcements (PSAs). (The Mediabot is different from the Googlebot, which maintains Google's search index.)

Many websites use AdSense to monetize their content. AdSense has been particularly important for delivering advertising revenue to small websites that do not have the resources for developing advertising sales programs and salespeople. To fill a website with advertisements that are relevant to the topics discussed, webmasters implement a brief script on the websites' pages. Websites that are content-rich have been very successful with this advertising program, as noted in a number of publisher case studies on the AdSense website.

Some webmasters invest significant effort into maximizing their own AdSense income. They do this in three ways:

1. They use a wide range of traffic-generating techniques, including but not limited to online advertising.
2. They build valuable content on their websites that attracts AdSense advertisements, which pay out the most when they are clicked.
3. They use copy on their websites that encourages visitors to click on advertisements. Note that Google prohibits webmasters from using phrases like "Click on my AdSense ads" to increase click rates. The phrases accepted are "Sponsored Links" and "Advertisements".

The source of all AdSense income is the AdWords program, which in turn has a complex pricing model based on a Vickrey second price auction. AdSense commands an advertiser to submit a sealed bid (i.e., a bid not observable by competitors). Additionally, for any given click received, advertisers only pay one bid increment above the second-highest bid.