As Microsoft anticipates a
richer “apps” ecosystem for Windows 8, they appear to be taking some extra steps to shield users from malicious applications with the introduction of an in-built file verification policy
powered by the SmartScreen Filter.
Originally a feature from Internet Explorer but now also (annoyingly) integrated in Windows Live Messenger 2011, SmartScreen is practically a dynamic list of known “illegal, viral, fraudulent, or malicious” URLs that Microsoft manually or
algorithmally identifies. It uses this list to compare the link or executes a user visits or downloads, warning if there’s a match.