Internet should be smoother. And in that case every website should use AJAX as much as possible. Do you know how much I hate to refresh when I was using Dial-Up connection.
Using AJAX will reduce data transferring. And It will attract user more. But AJAX is not the only solution on this. We should help internet to make internet a better place. Internet browsers compatibility on HTML5 will help this too.
HTML5's video player will reduce using Flash Player. Then Plug-in will not need to watch pretty web-pages. Thanks HTML5