Reports results of a study to explore how well six popular Web search engines performed in retrieving specific electronic finding aids mounted on the World Wide Web. A random sample of online finding aids was selected and then searched using AltaVista, Excite, Fast Search, Google, Hotbot and Northern Light, employing both word and phrase searching. As of February 2000, approximately 8 percent of repositories listed at the 'Repositories of Primary Resources' Web site had mounted at least four full finding aids on the Web. The most striking finding of this study was the importance of using phrase searches whenever possible, rather than word searches. Also of significance was the fact that if a finding aid were to be found using any search engine, it was generally found in the first ten or twenty items at most. The study identifies the best performers among the six chosen search engines. Combinations of search engines often produced much better results than did the search engines individually, evidence that there may be little overlap among the top hits provided by individual engines.

Accepted for publication in Physics World (January 2007) / With the vast majority of scientific papers now available online, this paper (accepted for publication in Physics World) describes how the Web is allowing physicists and information providers to measure more accurately the impact of these papers and their authors. Provides a historical background of citation analysis, impact factor, new citation data sources (e.g., Google Scholar, Scopus, NASA's Astrophysics Data System Abstract Service, MathSciNet, ScienceDirect, SciFinder Scholar, Scitation/SPIN, and SPIRES-HEP), as well as h-index, g-index, and a-index.