Where I work, we're seeing open rates on a mobile device as making up 50% of all opens. And we would not project our audience to be on the cutting edge of technology. Even if we're wrong and our subscribers are on the cutting edge, 50% is huge. Which points out an interesting opportunity for emailers.
Here's a recent screenshot from my iPhone. Now more than ever, the text that appears at the top of your email matters - even before someone opens, it's now another opportunity to entice readers to open. To be sure, this isn't entirely new - Gmail and other web-based email programs have shown you a preview for years, but in an increasingly competitive inbox, are you squandering an opportunity?
In this short sample alone, three emails simply repeat the subject line and two more have their "View this on our website," a hold-over from when lots more people had BlackBerrys which would display the HTML version instead of the Text version but then strip out all the formatting and pictures.
Even still, a short teaser above the "View as webpage" could entire BlackBerry and Text Version users more than just launching straight into the "View as webpage" as if you just naturally assume they will *want* to.