RDF-in-Mozilla Frequently Asked Questions

RDF serves two primary purposes in Mozilla. First, it is a simple, cross-platform database for small data stores. Second, and more importantly, the RDF model is used along with XUL templates as an abstract "API" for displaying information. RDF in 50 words or less is a quick, high-level description of what RDF does in Mozilla. The Back-end Architecture document describes in more detail how Mozilla's RDF implementation works, and gives a quick overview of the interfaces that are involved.

http://www.mozilla.org/rdf/doc/faq.html