Another approach is to incorporate gifs into your design to get users to stay in the email longer. This example from Your Karma leads with the brand’s main selling point, its premium features. Then they call out the savings users get when they sign up. It’s like saying, “Hey, we have the best features. You can enjoy them too and save big if you act now.”
The criteria and metrics can be classified according to its type and time span. Regarding the type, we can either evaluate these campaigns "Quantitatively" or "Qualitatively". Quantitative metrics may include "Sales Volume" and "Revenue Increase/Decrease". While qualitative metrics may include the enhanced "Brand awareness, image and health" as well as the "relationship with the customers".
In other words, your content is presented in a way that’s fun to consume, but still delivers real value at the same time. This one approach has allowed me to dominate in virtually all the markets I’ve written emails for — even when using a weak sales letter to a small list. And while I now use dozens (well over 50) ways to use infotainment in my emails, the following 3 ways alone can get the job done no matter what kind of product or service you sell.