“We‚Äôre starting to see the first round of sites and pages breaking due to the CSS fixes we have made. We would like to ask your help in cleaning up existing CSS hacks in your pages for IE7. It is has been our policy since IE6 that under quirks doctype we will not make any behavioral changes so that existing pages will continue to render unmodified, but under the strict doctype we want to change behavior to be as compliant as possible with the web standards.”
Link:
http://blogs.msdn.com/ie/archive/2005/10/12/480242.aspx


