Users of RSS content use software programs called "feed readers." The user subscribes to a feed by entering a link to the feed into the reader program. The reader can then check the user's subscribed feeds to see if any of those feeds have new content, and if so, retrieve that content and present it to the user. RSS delivers its information as an XML file called an "RSS feed." A number of feed readers are available, including free ones. A majority of feed readers are software applications you can download and install, although some are Web-based services that work within your browser.