In one of the most popular sessions at the DMA net.marketing show this week, Peter Cobb, eBags VP Marketing, reminded us of how similar Web site design is to brick and mortar store layout. Smart retailers analyze their floor layout and displays to maximize the selling power of every square foot of their store. Cobb says the same is true for his site, "Every pixel has to pay its way on the site. We analyze every link."

However, Cobb has a major advantage over brick and mortars -- he can split his site traffic. Every time eBags makes an alteration to its home page, half the incoming traffic is sent to one version and half to another version. Cobb carefully tracks results and the version that's more profitable wins. He hopes that by constantly testing and refining the page, the site itself will become more and more "optimized" for profitability.

One recent test bore striking results. 50% of eBags traffic got a version of the site with a sweepstakes pop-up box, while the other 50% of traffic saw the same sweeps box art incorporated into the page. The pop-up box won hands down, with five times the response rate!