The phrase describes a type of online program where individuals receive compensation for reviewing electronic messages. A user typically registers with a service, confirms their email address, and then receives advertisements or promotional material in their inbox. Remuneration is provided for each email the user opens and views, often requiring a click on a confirmation link within the message.
The emergence of these programs is rooted in advertising strategies aiming to bypass banner blindness and reach consumers directly. Businesses seek more effective engagement metrics than simple ad impressions, and these services offer a quantifiable measure of user interaction. Early examples focused on providing small financial incentives to increase visibility and drive traffic to websites or offers.