We spend more time using our phones to read email, take pictures and update our Facebook accounts then we do actually using it to talk. And the growth of smartphones doesn’t seem to be subsiding with half of all Americans now owning a smartphone. We looked at nearly one billion data points for this mobile study to see how this growth was affecting email, and the numbers were clear: if you don’t know how many of your subscribers are reading your emails on a mobile device and you don’t have a mobile email strategy, you’re about to miss out on the next gold rush.