USASearch.gov has a new program for searching Web sites of all federal, state, local, and tribal governments, as well as U.S. territories.

Vivisimo, an enterprise search company, on Thursday announced that it has expanded its search affiliate program, which offers a free search engine for all government Web sites. The search indexes more than 50 million government documents.

The expansion means that managers of government-related Web sites can add new features to their sites and even ambiguous search terms will extract useful information, Vivisimo said. The free search platform covers news, images, frequently asked questions, maps, and weather forecasts, as well as government contact information, applications, and notices regarding jobs and benefits.

The company designed the Vivisimo Velocity Platform to provide a clean interface, and simple and convenient navigation.

"Using Vivisimo's superior search technology, and the expanded search affiliate program, anybody can easily access the vast amounts of information collected and generated by the U.S. government," Raul Valdes-Perez, CEO and co-founder of Vivisimo, said in an announcement. "Vivisimo's intuitive user-interface turns complexity into simplicity -- and will help millions of people to get quick, authoritative answers to their questions."

In addition to USASearch.gov, the National Library of Medicine, Womenshealth.gov, the governments of New Zealand and Israel, and enterprise users use Vivisimo's search technology, which is based on a service-oriented architecture. The latest version of Velocity's enterprise search platform includes Web 2.0 functionalities, like social tagging, social bookmarking, social networking, and mash-ups.

Government website managers interested in using the USA.gov free search engine can sign up to use the service online.