which is the most common use of opt-in e-mail marketing
Email marketing A common example of permission marketing is a newsletter sent to an advertising firm's customers. Such newsletters inform customers of upcoming events or promotions, or new products.[14] In this type of advertising, a company that wants to send a newsletter to their customers may ask them at the point of purchase if they would like to receive the newsletter.
Viral marketing The ultimate goal of marketers interested in creating successful viral marketing programs is to create viral messages that appeal to individuals with high social networking potential (SNP) and that have a high probability of being presented and spread by these individuals and their competitors in their communications with others in a short period of time.[9]