It’s new!
It’s cool!
And now it even got a name! Ajax.
The funny this is that it is quite old and it has been used for a long time already. It just wasn’t hyped before.
Also this phenomenon clearly illustrates the dissatisfaction with the current static Html document standard common to the world wide web. Don’t deny it: html sucks for user interfaces! Html is a format for documents notuser interfaces.
A child of Html could make a nice User Interface definition; main thing would getting rid of awquard javascript. Using a more dynamic Document Object Model, and espacially a consistant one, with some kind of Intermediate Language providing power but still security like Java, or .Net or maybe a new one, which should be hosted by the browser itself instead of a nasty plugin noone has, would be perfect.