This document discusses responsive email design and its importance. It notes that 52% of consumers now access email on mobile devices. Mobile email opens increased 21% in 2013 and may account for up to 70% of opens depending on the audience and email type. While only 7.6% of time spent on mobile devices is reading email, email is still important. The document recommends frameworks like Zurb Ink for building responsive emails and notes challenges like supporting Outlook. It provides best practices like setting cell widths and inline CSS and tips like creating large images and considering data plans.