From USDOJ:
On April 9, 2012, the Department of Justice released version 2.0 of its Open Government Plan which detailed the Department’s “ongoing and anticipated efforts to increase openness” and which announced new Department initiatives concerning the administration of the Freedom of Information Act (FOIA). A key FOIA initiative in the Department’s Open Government Plan is the development of metadata standards “that will facilitate the ability of interested persons to search for and retrieve documents across websites and disparate record keeping systems.”
Put simply, metadata is “data about data.” Metadata provides a description and important facts about material that is posted online and is itself machine-readable and can be searched by other computers. When related documents, such as FOIA documents that are proactively disclosed in agency FOIA Libraries, are posted with uniform metadata it is far easier to locate them during a search of the Internet. Because of the value that metadata adds to search capabilities, the Department’s Office of Information Policy (OIP) is introducing a uniform metadata “FOIA tag” for agencies to use when they post FOIA processed data and documents online in agency FOIA Libraries.
Through the consistent use of this standardized “FOIA tag” in posting records in their own FOIA Libraries as outlined below agencies will in effect create a “virtual” government-wide FOIA Library by allowing the public to run simple, topical keyword searches that will efficiently retrieve documents from across the universe of Federal government FOIA Libraries. Such searches will be able to be conducted naturally through commercial search engines that are already used by millions of people every day, by combining any topical keyword with the term “FOIA.” OIP will be issuing further guidance to agencies on this topic in the months ahead and plans to customize features on FOIA.gov so that users have the option to access all FOIA-tagged documents across the federal government from one single location.