when I first saw this in action I got really excited because its exactly the right idea. Two major problems tho... first, it clashed with google maps. The map just didn't show up anymore when the page loaded dynamically. If I reloaded the page it appeared again. Maybe this is a google maps glitch and not ajax? I decided not to adventure very deep into the problem.
Secondly, I use the boilerplate theme and the footer was repeated inside the #content div. The footer is not in the #content div.
Maybe i could have fixed this in the html but did not try because the google maps problem would have been a longer problem.