[psnj]

> Can you show me some statistics to prove that this > (junk mail) works?

One could argue that it must be effective, as it's expensive to print and post mail, yet marketers have been doing it for decades. Its results are also generally more measurable than those of mass market advertising.

> You have no other means to reach your customer

On the contrary, (addressed) direct mail is generally sent to as targeted a market as possible. If you know your market, you're generally better off putting a lot of resources into a well-qualified set of prospects, than taking a more "shotgun" approach.