if the ajaxian page were just a link, there would be a percentage of people who would see the image/explanation and then decide not to click through. they were

if the ajaxian page were just a link, there would be a percentage of people who would see the image/explanation and then decide not to click through. they weren't interested in it, and so they don't use up the guy's bandwidth. with the iframe, those people use up the bandwidth whether they want to see it or not.