Probably the most commonly used medium for direct marketing
is direct mail, in which marketing communications are sent
to customers using the postal service. In many developed
countries, direct mail represents such a significant amount
of the total volume of mail that special rate classes have
been established. In the United States and United Kingdom,
for example, there are bulk mail rates that enable marketers
to send mail at rates that are substantially lower than
regular first-class rates. In order to qualify for these
rates, marketers must format and sort the mail in particular
ways - which reduces the handling (and therefore costs)
required by the postal service.
Direct mail permits the marketer to
design marketing pieces in many different formats. Indeed,
there is an entire sub sector of the industry that produces
specialized papers, printing, envelopes, and other materials
for direct mail marketing.