Earlier quoted context omitted.
I think you're being too mild in your side note. The first half of the IE6-9 era was part of a deliberate scorched-earth strategy to harm the open Internet, and the second half was them furiously backpedalling from that when it failed. It wasn't a technical decision, it was cynical business strategy, and having their IE brand get trashed is the least of what they deserve. I'm kind of annoyed with how quickly people a…
It certainly wasn't an act of altruism, but the entire modern web can trace it's AJAXy roots back to Microsoft's decision to eschew web standards. Microsoft added XMLHttpRequest to Internet Explorer so that they could develop Outlook Web Access. IE may have had utterly stank HTML compatibility, but adding XMLHttpRequest and inventing AJAX was probably the single most profound changeset in the history of the web.
[I think this proves what i said right](http://www.paulirish.com/2012/box-sizing-border-box-ftw/)