With the newest releases of Yahoo! Mail and Microsoft Windows Live offering preview panes as their default option, e-mail marketers must now discipline themselves to get the message across in the first few inches of space.

The new e-mail designs are a challenge for Internet marketers, especially on the business-to-consumer side. Business-to-business marketers have worked with this layout for years as a result of widespread corporate use of Microsoft Outlook. But as individual e-mail users migrate to online mail programs like Yahoo! Mail and Google Mail, messages now have to pop off the pane like never before. Analysts say that e-mail recipients scan this area of the e-mail window quickly before determining whether or not to hit the delete key.

Many marketers have no idea how their e-mails appear to recipients. Direct marketers typically develop a campaign, note how the creative renders on their own desktop machine, and hit the send key. Experts say this isn't always efficient: "Nine times out of 10, when I show them how their templates look when they get there, they're shocked," says Stefan Pollard, director of consulting services for e-mail software provider EmailLabs. "The images are turned off and all the calls to action are in the image. No one knows where to click on the e-mail so they're just opening it and deleting it."

Ensuring that the message appears just right is vitally important, especially given the amount of spam that recipients seek to filter out. Pollard knows that audiences have mere seconds to make a decision: "If they look in that preview pane and all they see is your broken masthead and some administrative copy that says, 'If you can't see this e-mail, click on this link,' then you've delivered no value in that message, and that two to three seconds in which you wanted them to do something turns into them clicking 'delete,' or 'report as spam.'"