IE8 Standards Mode Opt-In is Back?

In the early stages of Internet Explorer 8 development, Microsoft planned on requiring every web site that used the proper web standards to include an additional, non-standard tag for the site to work as expected. Developers were frustrated with having to break from standards to get the benefit of using the established standards and Microsoft decided against this approach. Sitepoint has an interesting article about a recent addition to Internet Explorer 8 that is eerily similar the original plan.