A feed is a data format (usually XML) that provides users with frequently updated content. Many sites publish a feed (RSS, Atom, RDF are some of the formats) and Quam Plures provides this functionality. There are tools known as "feedreaders" that allows one to subscribe to a feed. The feedreader checks the site on a regular basis to see if the site has been updated with new content. When the feedreader is told that new content has been posted, it is provided with the content title, a link to the content, and either an excerpt of the content or the whole content. Each feed contains a list of content that is published over time and the feedreader checks for new content when it visits the site. The feedreader allows a quick way to know when a site has updated content instead of having to visit the site; this is especially useful when one has several sites of interest. All one has to do is add the syndication link provided by clicking on the syndication links to the list in the feedreader.