Microsoft is improving Silverlight in every new release. the new thing i noticed from many others, is a better version information for currently installed Silverlight runtime through right-click context menu. It shows complete version info including build numbers. User can also set Silverlight Update options under the Updates tab.
Adobe Flash only shows major version number when you right-click on Flash content. When you click About Flash Player 9, it opens new browser window and redirect you to a page which contains a Flash movie and JS code to detect and show the Flash Player version. Its a bit lengthy process i suppose.
// chall3ng3r //