In a public effort to encourage Microsoft to add as much CSS 2 support as possible as its developers embark on IE7, Håkon Wium Lie (CTO of Opera Software and the father of CSS) and the Web Standards Project have begun the development of a test suite, known as “Acid2.”
"To ensure that IE 7 does not become another failed promise, the Web community will issue a challenge to Microsoft. We will produce a test page, code-named Acid2, that will actively use features Web designers crave, such as fixed positioning of elements.
...To the IE 7 developers, I want to say:
You are smart and talented. You know Web standards as well as anyone. You were capable of fixing IE in the past, but your managers didn't let you. You now have a new chance to get it right--don't waste it. Download Acid2 when it's released and get in touch if you think it's unfair for any reason. Resist pressure from management to ship before you are done--spend the extra time it takes.
...To the Web community I want to say: Microsoft has now been challenged. They will respond, if enough people remind them of the challenge. Please remind them. And, when IE 7 is released, make sure this is the first thing you type into it