Email whose purpose, as a whole or in part, is to sell or advertise a product or service or if its purpose is to persuade users to perform an act, such as to purchase a product or click to a Web site whose contents are designed to sell, advertise or promote.

Combining Email Marketing with Other Types of Marketing
Whether you choose to do your marketing online or offline, one thing does not change. This is the concept that no single marketing strategy will be as effective as a combination of two or more marketing strategies.