I have mod points but what the hell - this is bull. Everyone knew IE wasn't even following the standards of the day. The problem was that MS was busy tying IE and Windows together to migrate one monopoly into another and worse, IIS was serving deliberately broken HTML to make IE appear faster since MS had control of both ends of the equation.
IE was the standard on Windows, and it was even available in Mac and Solaris although those didn't really use the same code base or rendering engine so to say IE was the standard is disingenuous at best because IE on Windows wasn't even compatible with IE on Mac which actually had far better CSS support. Also, lets not forget that before Firefox, there was Mozilla which was the result of Netscape open sourcing Netscape 5 which was in development in the late 90s. Since they pulled a lot of commercial code out of it, the early builds were pretty badly broken but that was all we had on Linux and the web was a mess mainly because of Active X, rather than HTML. And that is where it really comes down to it, you can work around problems with HTML in different browsers, but Active X was an MS only technology developed specifically to do an end run around Java Applets. Both AX and Java Applets were a terrible idea.
Let's look at 2002 or so when IE6 was king of the hill. MS had IE for Mac still but the Solaris port was long gone. Apple looked at Mozilla's Gecko and KDE's KHTML and chose the latter to build a new browser around and they forked it to produce webkit but contributed the changes back as required by the license. In 2003 Safari appeared with OS X Panther and MS threw a shit fit and took their ball home declaring it impossible for them to develop IE on Mac when Apple clearly had info about the platform that would make Safari better (hint MS, only you did that) so the long slow decline of IE started as Apple pushed Webkit forward towards HTML5 standards, Mozilla stripped all the crap (email and news client) and released Firefox and eventually webkit found its way into other browsers, and then dominated tablets. In the end, it is tablets and phones that have proven the undoing of IE because while Firefox and Chrome have done well on Windows, IE is still quite popular, but really people are using desktops less and less and phones and tablets more and more so sites have to work with those and this means the same sites also work well with webkit and gecko based browsers so the thing that kept MS on top is gone.
People knew way back what MS was doing, but managers and developers using MS tools didn't care and so they put out non-standard sites and now that is coming back to bite them. The question is, are we doing it all again with Webkit at the expense of Gecko? Shouldn't MS be claiming to be Webkit rather than Gecko?