An e-mail in which recipients can buy goods and services directly from the e-mail message without being redirected to the retailer's Web site.
Marketers have consistently shown that transactional e-mail leads to significantly higher conversion rates, meaning more people convert from shoppers to buyers when they receive a transactional e-mail versus a regular e-mail. It's understandable considering that within the body of the message of a transactional e-mail, the recipient can view merchandise, select items, and submit an order. Just like on an e-commerce site, when the order form is completed, the customer clicks the "submit" button (and can then resume reading their other e-mail messages).
Here's a great example: Zagat's, a well-known distributor of restaurant guides, tried transactional e-mail sales for the 2000 holiday season, allowing customers to buy restaurant guides directly from the body of the e-mail message, rather than just including a link to their Web site. The campaign attained conversion rates five times as high as those of regular e-mail marketing. They believed this high conversion was due in large part to impulse purchases because the transaction could be completed before the customer grew weary of the procedures involved.