Steve Rubel writes a insightful post on why we won’t be carrying more and more devices, and why there won’t be more than three “screens” for marketers to target. We’re simply out of pockets.

Read Steve’s post here: We’re Out of Pockets.

But there are more reasons we won’t be carrying e-paper devices in the long run. The same reason the cell phone, PDA, camera and mp3 player are not separate devices any more. It’s because they can converge and because they can do more together. (And also - because there’s a limited number of battery chargers one can bring on a trip.)

In fact, screen one (the TV) and three (the cell phone) is now becoming a single screen, as mobile TV seems to be the next big thing in cell phones. And a lot of content for screen two (the computer) has been able to reach our cell phones for a while. What marketers need to think about is the way the context where messages reach us is changing. I’m no longer necessarily in my sofa when that ad hits screen one.

But then there are the early adopters, and that’s the reason new technology is going to end up in stand-alone devices. After it has been proven successful in the market, it will end up integrated into our limited pockets.