NOTE: As of January 2007, Feedflow appears to be out of service. From their site: The Updated Feeds API returns an RSS 2.0 list of feeds that have been updated after the given time stamp. If a feed has been updated multiple times, it is only displayed with the most recent time stamp. Each item represents an updated feed. The link element is the URL of the feed's HTML location. The guid element is the URL of the source feed. The pubDate element is the time the feed was most recently updated.