The document discusses key insights about mobile email usage and optimization. It shows that mobile email opens have grown 600% from 2011-2016, with over 70% of emails now being opened on mobile devices. When emails look bad on mobile, over 80% of users will still read them. The document provides tips for optimizing elements like preview text, links, text sizes, touch targets, and layouts for mobile. It also discusses different mobile email design approaches and resources for templates.