Just saw a link off Digg to an entry on the on the Microformats wiki about something called AHAH (Get it? "Aha!"). The article headline describes it as "AJAX 2.0," and breathlessly explains that is "backed by David Hansson, the creator of Ruby on Rails." The wiki entry for it introduces the concept thusly:
This fairly silly stuff, even from the perspective of your normal level of silly AJAX/Web-dev hype. Maybe it's getting the double dose by way of its association with Rails.
Never mind the "AJAX 2.0" thing. That just raises all kinds of weird questions -- If AJAX is Web 2.0, and this 'AHAH' stuff is AJAX 2.0, does that mean that AHAH is then Web 4.0? This makes my head hurt.