A reading list is an OPML document that contains a list of feeds. The NewsRiver aggregator, which runs as a Tool inside the OPML Editor, has been extended so that users can subscribe to reading lists. When the editor of a reading list adds a feed, subscribers to the list will automatically read that feed in every scan. Likewise, when a feed is removed, it will no longer be read in a scan. It's a way for readers to delegate the act of subscribing to experts in subjects they are interested in.