In an impressive volte-face, Microsoft has decided that Internet Explorer 8 will default to being compliant with web standards after all, and will not, as previously announced, require web pages to explicitly opt in to conforming behavior.

Internet Explorer presently has two modes for displaying web pages: "quirks" mode, for showing old or particularly badly-formed pages, and "standards" mode, for showing pages that appear to conform to the various specifications that govern the web. The problem with this was that IE 7 doesn't honor the standards very well, and so its "standards" mode isn't all that standard.

IE 8, due to go into private beta imminently, is set to be a huge improvement on this front, and should be a truly standards-compliant version of Internet Explorer. This had Microsoft concerned. The obvious thing to do would be to make "standards" mode more standard. The part of this that concerned the company was that there are pages out there that put the browser into "standards" mode, but aren't actually standard—instead, they depended on IE 7's nonstandard "standards" mode.

To address this, Microsoft said that developers would have to opt in to true "standards" mode. Otherwise, web pages would be stuck with a kind of "IE 7" mode. This plan caused a considerable reaction in the web development community. Although many were sympathetic to Microsoft's desire to not "break the web," the general consensus was that this move would retard web development even further and undermine the entire purpose of web standards.

Surprisingly, Microsoft has changed its mind. Internet Explorer 8 will default to true standards compliance after all, and developers who want IE 7 behavior will have to explicitly choose it. Microsoft is citing its new interoperability initiative as the impetus behind the change. This move, designed primarily to stave off further EU intervention, emphasizes support and promotion of open standards in a way that the company hasn't previously done. This move should also help to fend off Opera's antitrust complaint, which argues that the EU should force IE into better standards compliance.

Although I'm glad to see the change (I understood why they wanted to have the opt-in behavior, but I didn't agree with it), it's not entirely clear why the company has changed its stance. The arguments that were made at the time of the original announcement were not unexpected or surprising; Microsoft knew what the criticisms would be and attempted to justify its choice in spite of them. Nothing has really changed between now and then, and Microsoft's argument for the opt-in behavior is just as strong now as it was six weeks ago.

If the company honestly believed that its approach was, from a technical perspective, the best one—and the software giant certainly put quite some effort into designing and defending it—then it should be of some concern that politics should have caused it to switch. Don't get me wrong—I'm glad that they're going to make "standards" mode standard. I just wish they were doing so for the right reasons.