If your claim is that Google popularized the ideas behind Ajax, then I'll happily agree: The term Ajax was invented outside Google [0] to describe Gmail front-end inner workings. My first contact with Ajax-like technologies was certainly Gmail in 2004 and not OWA in 2000, so I am not denying the merits of popularization. But I think even saying Google "developed the technology into" Ajax is unfair to OWA, given that Microsoft was pushing the other components of Ajax for a lot longer as DHTML (which led to standardizing DOM [1]; document.all anyone?) and OWA used DHTML+XHR, which was at the time essentially a non-cross-browser version of Ajax (props to Mozilla for implementing a compatible version of XHR and shipping it as part of Mozilla 1.0 in 2002).

I won't argue for Microsoft any further, though, because the "cross-browser" part is key. The fact that they invented and shipped these things in IE with no effort to standardize them (as part of their embrace, extend, extinguish approach) was a big headache for cross-browser compatibility. Google gets most of the credit for Ajax because web developers hated Microsoft's approach to the web at the time (for very good reason). It is interesting to compare Microsoft's behavior back then with Google's current approach of flooding standards bodies with (at times half-baked) proposals.

[0] https://web.archive.org/web/20150910072359/http://adaptivepa... [1] https://www.w3.org/DOM/faq.html#DHTML-DOM