Maintenance of Ruby 2.0.0 ended on February 24, 2016. Read more
Atom is an XML-based document format that is used to describe 'feeds' of related information. A typical use is in a news feed where the information is periodically updated and which users can subscribe to. The Atom format is described in tools.ietf.org/html/rfc4287
The Atom module provides support in reading and creating feeds.
See the RSS module for examples consuming and creating feeds