The American Association of Advertising Agencies commissioned a survey that showed that nearly 60% of Internet users have responded to a promo or coupon they received through an email. My own experience with many of our clients has shown how effective email marketing can be. That said, there is a fine line between an effective email campaign and spam, and it is important to walk that line intelligently. Companies spend huge sums building and protecting their brands. Email marketing can be a great boon, but done poorly, can hurt consumer trust in a brand.