Major Search Services in Government

There is ongoing work under the E-Government Act to
prepare recommendations on search interoperability.
Our interest in search technologies includes database
query as well as information retrieval, and includes
facilities for internal government use as well as
those supporting public access (see draft "Statement
of Requirements for Search Interoperability" at
http://www.search.gov/interop/requirements.html )

As part of that work, I am seeking a rough sense of
how many different search technologies are now in
common use. If you are aware of such a list of major
search products/services in use across government
(especially but not exclusively, the U.S. Federal
Government), please let me know. I have in mind to
compile a list as products/services are suggested,
similar to the attached skeleton HTML page.

Eliot