In my view direct mail marketing is the customized and tailor made marketing strategy that is used by the companies to directly reach out the customers. In this the customer can be directly contacted through the mail and hence the content used per customer may be different. It can help to reach out to individual customers and that can improve the trust factor in them until and unless the information shared in the mail is of some use to the customers. In order to generate the lead you can setup various lead generation technique
I use direct mailers with my company and have been for going on 4 years. I would say the sweet spot, as for cost, is on avg. about 30 bucks a pop. Best close ratio compared to many other marketing.
direct mail marketing refers sending your promotion directly to the users inbox. it's very effective.