Another leading effort was the one of the Library of Congress with its Experimental Search System (ESS). The ESS was "one of the Library of Congress' first efforts to make selected cataloging and digital library resources available over the World Wide Web by means of a single, point-and-click interface. The interface consists of several search query pages (Basic, Advanced, Number, and a Browse screen) and several search results pages (an item list of brief displays and an item full display), together with brief help files which link directly from significant words on those pages. By exploiting the powerful synergies of hyperlinking and a relevancy-ranked search engine (InQuery from Sovereign Hill Software), we hope the ESS will provide a new and more intuitive way of searching the traditional OPAC (Online Public Access Catalog)." (excerpt from the website in 1998) Another interesting - and totally different - initiative was the creation of the Internet Public Library (IPL) by the School of Information and Library Studies at the University of Michigan. The IPL went live in March 1995 as the first U.S. digital public library to serve the internet community, and to catalog websites and webpages. The librarians' task was to choose the best documents available on the web, and process them as library documents for them to be easily accessed from the IPL website, that acted as a portal. The IPL sections were: Reference, Exhibits, Magazines and Serials, Newspapers, Online Texts, and Web Searching. There were also Teen and Youth sections. All items were carefully selected, catalogued and described by the IPL staff. As an experimental library, IPL also listed the best internet projects that were run by librarians, in the section Especially for Librarians. Since then, students from the IPL Consortium, a consortium of colleges and universities with programs in information science, have worked on maintaining and developing the IPL as a public library for the web. # Union catalogs In 1999, the two main union catalogs were WorldCat, run by OCLC (Online Computer Library Center), and RLIN (Research Library Information Network), run by the Research Libraries Group (RLG). What exactly is a union catalog? The idea behind a union catalog is to earn time by avoiding the cataloging of the same document by many catalogers worldwide. When catalogers of a member library catalog a new document, they first search the union catalog. If the record is available, they import it into their own library catalog and add the local data. If the record is not available, they create it in their own library catalog and export it into the union catalog. The new record is immediately available to all catalogers of member libraries. Depending on their status, experience and quality of cataloging, member libraries can either import records only, or import and export records.