The Extensible Markup Language (XML) is a flexible, nonproprietary setof standards for annotating or “tagging” information so that it can betransmitted over a network such as the Internet and readily interpreted bydisparate computer systems. 1 It is increasingly being promoted by information technology (IT) developers as the basis for makingcomputerized data much more broadly accessible and usable than haspreviously been possible. As a result, many organizations, including bothprivate businesses and federal government agencies, are buildingapplications that try to take advantage of XML’s unique features. Given thewidespread interest in adopting this new technology, the chairman of theSenate Committee on Governmental Affairs asked GAO to assess (1) theoverall development status of XML standards to determine whether theyare ready for governmentwide use and (2) challenges faced by the federalgovernment in optimizing its adoption of XML technology to promotebroad information sharing and systems interoperability.