"Web users can now search the catalogs of more than 10,000 libraries worldwide through WorldCat.org, a site that offers a downloadable search box."
The search box can be downloaded from WorldCat.org site to library Web sites, museum sites, genealogy sites, book club sites, blogs etc
WorldCat was created in 1971 and is maintained by OCLC Online Computer Library Center, the world's largest library cooperative, and its member libraries that use information from and contribute to the database for cataloging and interlibrary loan."
As the world's largest computerized library catalog, WorldCat contains more than 70 million entries for books and other materials and more than 1 billion location listings for these materials in libraries around the world.
Source: Library Technology Guides