Perhaps because the design of those features were backed up by statistical improvement metrics? http://blogs.msdn.com/jensenh/archive/2006/04/11/573348.aspx htt

Perhaps because the design of those features were backed up by statistical improvement metrics? http://blogs.msdn.com/jensenh/archive/2006/04/11/573348.aspx http://blogs.msdn.com/jensenh/archive/2006/04/11/573348.aspx