Also known as "Shit that folds" - Direct Marketing is the businessman's way of explaining all that junk-mail
that accumulates in your letterbox. It's physical spam
Sometimes it's called Database Marketing, because in addition to printing and posting (sometimes) millions of mails, a company usually needs to mine a database in order to work out who talk to and what to say.
It's amazing how huge the industry is that produces this stuff, especialy given that most of this stuff becomes bin-fodder or hamster-cage lining material.