A web feed is an XML-based document which contains a sequence of content items. Web logs or blogs are a common source for web feeds. However, web feeds may also be associated with different sources other than blogs.
The term syndication is used to describe the availability of a web feed for an information source, such as a blog. This is also known as "publishing" a feed.
The term aggregation is used to describe the process of combining the contents of multiple web feeds, such as for display on a single web page. This is also known as "subscribing" to a web feed.
Web feeds are designed to be machine readable, so there is no requirement that they be destined only for user consumption. For example, business partners could use web feeds to exchange information without any user intervention.