Microsoft originally intended to add additional compliance support into IE7 (including the Acid 2 test), but it didn't make it into the shipping build. It was then put in a lower priority on the bottom of a large "wish list" of improvements for future updates, but to no avail as Microsoft focused its resources on building IE8. No version of IE has been able to pass the test, while mainstream competing browsers like Opera, and Apple's Safari have managed to be compliant for the last few years. Mozilla's upcoming version 3 of Firefox is also set to pass the Acid 2 test, although the current shipping version of Firefox (version 2) won't cut the mustard.

The real importance of standards compliance is a two-party problem: one for developers who have to laboriously make their sites work with as many browsers as possible, and another for the users who simply may not be able to use a site because it's been designed only for a limited number of compatible browsers. The Acid 2 test isn't the final solution, but it manages to put any browser through its paces with a seven-part test. Still no word on other IE8 user features, or a release date.

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