Direct marketing is a sub-discipline and type of marketing. There are two main definitional characteristics which distinguish it from other types of marketing or advertising. The first is that it attempts to send its messages directly to consumers, without the use of intervening media. This involves unsolicited commercial communication with consumers or businesses. The second characteristic is that it is focused on driving purchases that can be attributed to a specific "call-to-action." This aspect of direct marketing involves an emphasis on trackable, measurable results (known as "response" in the industry) regardless of medium.
The most common form of direct marketing is direct mail, where the marketers use a reduced "bulk mail" postal rate to send paper mail to all postal customers in an area or all customers whose addresses have been taken from a list. The second most common form of direct marketing is telemarketing, where marketers call selected (or random) telephone numbers. Email Marketing, including spam may have passed telemarketing in frequency at this point, and it is a third type of direct marketing. A fourth type of direct marketing, broadcast faxing, is now less common than the other forms. This is partly due to laws in the United States and elsewhere which make it illegal. A related form of marketing is infomercials. They are typically called "direct response" marketing rather than direct marketing because they try to achieve a direct response via television presentations. Viewers respond via telephone or internet, credit card in hand.
Direct marketers also use media such as door hangers, package inserts, magazines, newspapers, radio, television, email, internet banner ads, pay-per-click ads, billboards, transit ads, etc. And according to Ad Age, "In 2005, U.S. agencies generated more revenue from marketing services than from traditional advertising and media."
If the ad in the medium asks the prospect to take a specific action--call a free phone number, visit a website, return a response card, place an order, visit a PURL, complete a survey, etc.--then the effort is considered to be direct marketing. Direct response or direct-response advertising are both synonymous terms for direct marketing.