It is no doubt that using pass along e-mail to reach customers is low cost. Once we get the e-mail address from previous customers and members, we can send out the promotion e-mail to them. E-mail receiver will be always willing to forward the mail to their friends if they think it is useful and attractive. Through the word-of- mouth, people usually open the mail which is sent by their friends. Perhaps, it is one of the fastest and credible way to spread message.
However, pass along e-mail may not be successful sometimes. First, many promotion e-mail will be listed as junk mail, e-mail user will always neglect it. Second, e-mail user may feel annoying to receive the mail from the company, they may delete the message immediately. Third, pictures and text cannot be viewed when user open the e-mail (see the example blow).