• by David Goetzl  @dgoetzl, December 11, 2012

At the MediaPost Email Insider Summit, Dan Quintero, founder of AdStack, said data shows between 40%-60% of all emails sent is opened on a mobile device -- but 60% of individuals will click out if the email is not mobile friendly.

Design is critical so content is optimized for particular devices. The appearence needs to be effective whether opened on an iPhone or Android device -- and same for a landing page that an email can direct someone to.

Also, Quintero said people who check email on a mobile device are doing so at least five times a day.

Has mobile email reached a plateau? "We definitely see there's definitively an increase in mobile ... across the board," he said.