<A target="_blank" href="http://blogs.perficient.com/portals/2011/03/18/using-ajax-in-portal/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+PortalSolutionsBlog+%28Portal+Solutions+Blog%29">Glenn Kline provides a couple of scenarios of a portal in use</A> - without Ajax and with Ajax - and explains the difference.