Ormai gli acronimi si sprecano... 
Darren points to a cool article from
Adaptive
Path that gives a new term for the cool apps Google has
been building lately: Ajax (Asynchronous Javascript and XML).
Sure, XMLHTTP async calls are something web developers have been
doing for a while, but Google's "iPodded it"[1]. I'm looking
forward to those Client Callbacks in Whidbey, especially
if the Javascript is cross-browser.