Microsoft chairman Bill Gates was expected to announce <A HREF="http://www.ajc.com/business/content/business/ap/ap_story.html/Financial/AP.V0999.AP-Comdex-Gates.html">new junk email filtering technology</A> called SmartScreen at his keynote address Sunday at the annual COMDEX trade show in Las Vegas.The Atlanta Journal Constitution reports that the SmartScreen technology will be used in several products, but will first debut in 2004 in an add-on application for Microsoft's Exchange Server 2003. The technology will use algorithms to judge whether incoming email messages qualify as junk email and filter them out before they get to the end user's emailbox.