The term "drip marketing" is derived from the agricultural terminology for watering plants a small amount over a long period of time, hence "drip irrigation."
Drip marketing is an effective form of direct mail marketing as it reinforces your product or service a little at a time for a long period of time.
A drip marketing campaign keeps your direct marketing campaign in the forefront of consumers' and business' minds and gives you an edge over other direct mail marketing companies.