Reality: This myth is beginning to fade, but many U.S. executives and marketers still use CAN-SPAM as an excuse to avoid getting explicit permission before emailing. They haven't learned that CAN-SPAM is just a start. Permission, in fact, is the foundation of customer relevance and trust.

True, CAN-SPAM does not mandate opt-in. However, if you don't have "affirmative consent," the Act also requires you to include a statement in your emails such as "This is an advertisement." I can probably count on one hand the number of unsolicited emails I've received with this notice in the message.

Also, affirmative consent means your subscribers must actively request your emails. Un-checking a pre-checked box does not count.

More importantly, however, is customer control. Most recipients today recognize the difference between unsolicited and requested emails. Unexpected and unwanted email annoys them -- a lot. They'll let you know of their displeasure, not by clicking the unsubscribe button, but by hitting the spam-complaint button.

Various studies point to email marketing delivering the highest ROI of any marketing channel. But look more closely. You'll see that one of the major differences between email and other channels is the high permission level. Permission is not required, but if you want superior results, it is not optional.