Reality: People who move into email marketing from offline channels, especially direct mail, cling to this concept, where list size is directly related to revenue and ROI. There is often an incessant focus on list growth at all costs.

Again, email is different. Yes, growing your email database is important because you'll typically lose about one-third of your list annually through normal churn. Additionally, various studies suggest that one- to two-thirds or more of your list members are actually inactive (no opens or clicks for some extended time frame).

Therein lies both the challenge and opportunity. The reasons for that inactivity vary from list to list. However, we can trace some of it to any, or a combination, of these factors:

• How the names were acquired
• What was done (or not done) to engage new subscribers
• The relevance and frequency of your emails
• What was done (or not done) to reach out to subscribers who stopped opening, clicking or converting.

In fact, programs designed to engage new subscribers and convert existing list members into high-value, loyal customers pay off better than continually spending more money to attract new customers. So do efforts to reduce churn, such as letting subscribers choose format, frequency and content alternatives instead of just unsubscribing.

Email is the ideal channel for engaging subscribers through highly personalized and targeted approaches that continually delight and engage those hard-won customers. In the final "myth," we make the ROI case for moving to these more sophisticated email techniques.