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. In the US, marketers send over 90 billion pieces of direct mail per year.
You have to realize, whether you are a business with a physical presence or work completely online, marketing in the internet is something you have to work with and put to your advantage. This would mean that you could reach millions of people around the world. It is unsurprising, then, that businesses have been moving more and more of their marketing resources online.