Mobile Optimized or Responsive eMail designs? Before you go down the path of either, you need to go back to what your objective of the eMails are and what your customer experience will be with each on the major glass sizes. Both can be equally effective, but content and the amount of content will also impact your decision. Just remember that eMails opened on a mobile device that are not optimized or responsive will more often than not, give a bad customer experience. Over the next couple days, my updates will be on Responsive and Mobile Optimized eMail.