WorldCat is the world's largest bibliographic database, the merged catalogs of thousands of OCLC member libraries. Built and maintained collectively by librarians, WorldCat itself is not an OCLC service that is purchased, but rather provides the foundation for many OCLC services and the benefits they provide.
In the summer of 2003 OCLC started the Open WorldCat program. This program makes records of library-owned materials in the WorldCat database available to Web users on popular Internet search (like Yahoo! and Google by typing "find in a library: " before your search terms), bibliographic and bookselling sites.