Once upon a time, in the land of zero Gs, where Instant Messaging reigned supreme, there lived a boy without a cell phone—let alone one that was smart—who was happy to have a mere Hotmail account.

Alas, time has passed and that same young lad has more email accounts now than he can remember passwords. As for the ones he does recall, he certainly has no shortage of devices and platforms on which to check them.

And chances are, he’s checking those Living Social deals and New York Times headlines emails on his smartphone. That’s no fairy tale; it’s science. In the last six months (leading up to April), there’s been an 80 percent increase in the number of emails opened on a smartphone, 20 percent of which occurred on an iPhone—more than any desktop, webmail, or phone.

That being said, email marketers will do themselves a solid by learning more about their progressively mobilized audience if they check out this infographic from Litmus and Column Five. Take it from me a boy who knows.