XML is a great format for exchanging information because it balances readability, extensibility, and compatibility across heterogeneous environments. However, its flexibility is also a disadvantage because it is far too easy to create a proprietary XML schema, resulting in lots of custom code to interface with various systems. Lots of custom code leads to brittleness, and brittleness leads to frustration. The key to salvation lies in standardization.

Enter the Atom standard: a standards-track schema that defines a generic collection/item container format in XML. Most people equate Atom to an RSS competitor, which is true, but that only covers half of what it does. The Atom Publishing Protocol is a well-defined protocol for performing CRUD (Create, Read, Update, Delete) operations on items over HTTP. The Atom Syndication Format, which is the most commonly used portion, defines the XML schema used to deliver data during a Read operation. Atom was spearheaded by Sam Ruby, and is now back by people like Brad Fitzpatrick, Tim Bray, Jeremy Zawodny, Mark Pilgrim, and is heavily implemented by Google.