From HTML WG Wiki
A web feed is a data format used for providing users with frequently updated content. Content distributors syndicate a web feed, thereby allowing users to subscribe to it. Making a collection of web feeds accessible in one spot is known as aggregation, which is performed by an Internet aggregator. A web feed is also sometimes referred to as a syndicated feed.... web syndication refers to making web feeds available from a site in order to provide other people with a summary of the website's recently added content (for example, the latest news or forum posts).
Feeds are the primary means used by blogs, news sites, and other information sources to notify others about updated content on their sites.