An earlier information delivery system from Microsoft that provided a platform for "pushing" information to users from Internet content providers and internal intranets. Based on the Channel Definition Format (CDF), channel providers stored XML-based CDF files on their Web servers, which contained the URLs to the pages that made up the channel's offerings. When users selected a channel from their desktop, the underlying CDF file is accessed. The Active Channel was supported starting in IE 4 (Internet Explorer Version 4.0) and dropped in IE 7 due to the popularity of widely used syndication formats such as RSS. See Active Desktop, push technology and RSS.