A set of questions about a topic that’s used for research purposes. Questionnaires are commonly used in digital marketing to get feedback on user experience (UX). For example, you might send one after a customer makes a purchase to find out if they experienced any confusion during the checkout process. Marketers also commonly use questionnaires after someone unsubscribes from a newsletter or other mailing list.

The 3 Things To Avoid When Emailing Your List
When you decide to have an opt-in list, it is not just a matter of sending your subscribers your promotional newsletters or catalogs.