What's the difference between RSS and Atom? Both are XML formats, both are in common use, and most people who read RSS feeds don't need to know the technical differences between them. Atom was designed to resolve the incompatibilities among the various versions of RSS (0.92, 1.0, and 2.0) and is a bit more complex. It is also an Internet Engineering Task Force (IETF) specification, RFC4287. RSS 2.0's specification is less formally reviewed and approved, but is still a standard.

If you're curious about how they're structured, here's a page for you: Comparison of RSS 2.0 and Atom. The top of this page shows a schematic of each data format -- showing each element and its children -- and a sample file. This page goes on to a more technical discussion about generating each of these formats with JavaScript, but the schematics are handy and helpful.