RDF

A general framework for describing a Web site's metadata, or the information about the information on the site (see: meta-). RDF is based on XML and provides interoperability between applications that exchange machine-understandable information on the Web.

For example, it details information such as a site's sitemap, the dates when updates were made, keywords that search engines look for, and the Web page's intellectual property rights. Developed under the guidance of the W3C, RDF enables search engines to rely on metadata and allows users to share Web site information more readily.