Direct marketing is attractive to many marketers, because in many cases its effectiveness can be measured directly. For example, if a marketer sends out one million solicitations by mail, and ten thousand customers can be tracked as having responded to the promotion, the marketer can say with some confidence that the campaign led directly to the responses. By contrast, measurement of other media must often be indirect, since there is no direct response from a consumer. Measurement of results, a fundamental element in successful direct marketing, is explored in greater detail elsewhere in this article. Yet since the start of the Internet-age the challenges of Chief Marketing Executives (CMOs) are tracking direct marketing responses and measuring results.
While many marketers like this form of marketing, some direct marketing efforts using particular media have sometimes been criticized for generating unwanted solicitations. For example, direct mail that is irrelevant to the recipient is considered "junk mail", and unwanted email messages are considered "spam". Consumers are demanding more personalized direct marketing, which some advertising agencies are able to provide by using variable data printing and targeted mailing lists.