<A target="_blank" href="http://news.techworld.com/security/3291639/internet-explorer-9-hammers-rivals-in-download-blocking-test/?olo=rss">Application Reputation, a new feature in IE9, tries to create a list of applications</A> on the internet. Then, when you download files, it checks the list. If the app isn't in the list, IE9 blocks the download. Tests show the application is effective.