This field is for the spotlights that have a form to receive a coupon code via email in the sidebar of their Spotlight page. These forms are created in Contact Form 7, and the shortcode can be found under Contact in the left WordPress admin menu.
Enter a description of the coupon or ad here. This will be used as alt text for the ad image on the customer's Business Spotlight page so that users who use devices like screen readers will know what the image is.