When we released IE8, we said that our next steps started with listening to your feedback. A major part of what we heard, including comments to that same post, was that developers wanted more builds, more often. At the same time, given the high expectations of our users and the breadth of impact of changes we make to our platform, we need to carefully balance the quality of what we release with the frequency of releases. With the Platform Preview we want to strike a balance that provides developers an early and reliable hands-on experience with key parts of IE. With this Platform Preview, developers and people interested in standards and web development can try out new platform functionality and provide early feedback.
Link – http://blogs.msdn.com/ie/archive/2010/03/16/about-the-platform-preview.aspx
