Sure, you can make your e-mail advertising look like a Web page, with loads of content and complex HTML. But your mobile audience is walking around with a screen the size of a credit card. For five simple rules on designing e-mail for the portable inbox, continue reading on Direct Magazine.

Yes, you can make your e-mail advertising look like a Web page, with loads of content and complex HTML. But your mobile audience is walking around with an inbox-in-hand, reading e-mails, browsing the Web and making split-second decisions based on a screen that isn’t much bigger than a credit card.

The old technique of delivering a Web page to the inbox isn’t going to work. On the contrary, it’ll prevent clicks rather than encourage them.

Here are five simple rules to consider when designing e-mails for the 21st century inbox