E-mail marketing - 20% of e-mail sent by retailers is opened on a mobile device, Knotice study reports - Internet Retailer

One out of every five marketing e-mails a retailer sends is opened on a mobile device, shows a new study of millions of e-mail messages from direct digital marketing firm Knotice. Users of the iPhone represented the most avid mobile e-mail readers. And mobile readers typically view their messages early in the morning or late at night, the study finds.
Knotice examined a sampling of 155.3 million e-mails sent across 12 industry segments in Q4 2010. It breaks out e-mail activity by industry and by mobile device. Of the 12 industries measured, retail had the highest percentage of mobile e-mail readers.