Odd trivia: this label was invented only three months after Jesse James Garrett coined “AJAX”. The difference in momentum is explained by Ajax using abilities already available in deployed browsers — Internet Explorer was the first to support asynchronous XML requests, and “Ajax” became popular only after Firefox started supporting it too. “HTML5″ is the other way around… marketing occurs on features to be found in current and future versions of minority browsers, and there’s little provision for reaching the masses. “HTML5″ definitely has bigger buzz than “Ajax” here in 2010, though.
Happy birthday, little marketing label, you’re now five years old. Grow up and do good things.