Promotion involves disseminating information about a product, product line, brand, or company. It is one of the four key aspects of the marketing mix. (The other three elements are product management, pricing, and distribution.)

Promotion is generally sub-divided in the textbooks into two parts:

Above the line promotion: Promotion in the media (e.g. TV, radio, newspapers, Internet) in which the advertiser pays an advertising agency to place the ad
Mid line promotion: Promotion within the organisation (e.g. [to promote the workers working within the organization. to increase incentives etc...])
Below the line promotion: All other promotion. Much of this is intended to be subtle enough that the consumer is unaware that promotion is taking place. E.g. sponsorship, product placement, endorsements, sales promotion, merchandising, direct mail, personal selling, public relations, trade shows
The specification of these four variables creates a promotional mix or promotional plan. A promotional mix specifies how much attention to pay to each of the four subcategories, and how much money to budget for each. A promotional plan can have a wide range of objectives, including: sales increases, new product acceptance, creation of brand equity, positioning, competitive retaliations, or creation of a corporate image.