Microsoft invented XMLHTTP, an ActiveX object, not XMLHttpRequest, that is similar but not proprietary, and a part of Ajax. And Ajax is a term invented by Garrett - and not Microsoft - that includes several W3C formats.
"AJAX" the term is a meaningless bit of inaccurate noise (it is wrong in almost every way). No idea what your bit about XMLHttpRequest was, given that was nothing more than a formalizing and cross-platform implementation of Microsoft's COM object (which itself was originally written for Outlook Web Access).
Like the GP that bit about AJAX was just all wrong. Garrett is so astonishingly irrelevant in all of this, as is the AJAX me-too title. Google was very important, but only insofar as they legitimized the technique and made a lot of people realize that this crazy web thing was a lot more powerful than people often thought. And it wasn't gmail -- it was Google Suggests. That was an atomic bomb on webapps that proved that highly dynamic pages were possible and preferable.
