The key to successful marketing programs is the ability to speak to your customers as individuals and appeal to what is most important to them; one message does not fit the needs of every customer. Collecting preferences helps you understand these individuals and the subjects in which they have the greatest interest. This enables you to customize your messages and increase conversion rates.

Once you have this “self-declared” information, you'll want to tie it to the activity and behavior data you get from the emails you send: who opened what, which links they clicked, what are they buying and how often they buy. Doing so will allow you to further refine your messaging and content. For example:

§ A sports team sends out a regular newsletter updating fans on the team's latest news. If the team knows which player is a particular fan's favorite, it can insert additional content about that player into the newsletter. The team can also follow up with emails that keep the fan updated on special appearances the player may be making or merchandise bearing his image.

§ A hotel that collects information on a traveler's favorite activities—for example, golf or spa—can use that information to promote special tee times or spa specials to encourage the traveler to book a time before he or she arrives. When travelers get information on specials that are of interest to them, the hotel can sell additional services; it's a win-win for everyone.

§ A sporting goods store that knows that a customer is interested in skiing, tennis and yoga can feature items from those product categories in its weekly email promotions.

Collecting customer preferences allows you to have a better understanding of each customer's interests. This information becomes even more valuable when married with ongoing activity data, giving you a full view of your customer's buying behavior and what drives them to take action. Collecting and harvesting this information allows you to create more relevant email marketing communications, providing your customers with information they want—when they want it—to drive significantly higher sales conversion rates.