RSS is a family of Web feed formats used to publish frequently updated works – such as blog entries, news headlines, audio, and video – in a standardized format.[2] An RSS document (which is called a "feed", "web feed",[3] or "channel") includes full or summarized text, plus metadata such as publishing dates and authorship. Web feeds benefit publishers by letting them syndicate content quickly and automatically. They benefit readers who want to subscribe to timely updates from favored websites or to aggregate feeds from many sites into one place. RSS feeds can be read using software called an "RSS reader", "feed reader", or "aggregator", which can be web-based or desktop-based. A standardized XML file format allows the information to be published once and viewed by many different programs. The user subscribes to a feed by entering the feed's link into the reader or by clicking an RSS icon in a browser that initiates the subscription process. The RSS reader checks the user's subscribed feeds regularly for new work, downloads any updates that it finds, and provides a user interface to monitor and read the feeds.

The initials "RSS" are used to refer to the following formats: "Really Simple Syndication (RSS 2.0)", "RDF Site Summary (RSS 1.0 and RSS 0.90)", or "Rich Site Summary (RSS 0.91)".

RSS formats are specified using XML, a generic specification for the creation of data formats. Although RSS formats have evolved since March 1999,[4] the RSS icon ("") first gained widespread use in 2005–2006.