To many of us, searching the Web means Google.

With a 69.4 percent share of the search market as of March, Google certainly has dominance. The remaining four top search engines' market share: Yahoo, 14.8 percent; MSN/Live, 10.2; Ask, 3.7; and AOL, 1.5.

But while Google has the largest database of Web content, it alone is not always sufficient. Less than half the searchable Web is fully searchable by Google. Overlap studies show that more than 80 percent of the pages in a major search engine's database is available in only that search engine, according to the library at the University of California, Berkeley.

Some non-Google search engines may be specialized to do a better job finding what you are looking for, or may display the results in a more understandable form.

A good example of the second case is Clusty (clusty.com), a homegrown search engine that uses "clustering technology" to organize search results.

Clusty is a product of Vivisimo, a company started by three Carnegie Mellon University scientists and headquartered on Murray Avenue in Squirrel Hill.

In Clusty, search results come back sorted into categories. Clusty tells you how many results fell into each category. It is especially useful for a term that has varied meanings.

Clusty is an example of a metasearch engine. Metasearch engines do not build their own databases but use open databases, often from smaller search engines. Be aware that metasearch engines may not have access to the Google or Yahoo databases.

One metasearch engine that does have fairly wide access has the unfortunate name of Dogpile (dogpile.com).

Another search engine with Pittsburgh roots is Lycos. Started in 1994 as a research project by Michael L. Mauldin of Carnegie Mellon University, Lycos boomed and in 1999 was the most-visited online site in the world. It since has been sold several times and now is more of an entertainment portal, but you still can use it for search at Lycos.com.

There are myriad search engines that are specialized to search for particular kinds of data. If you go to search-engines-2.com you'll see a list of more than 12,500 links to search engines sorted by topic, country/region, meta and other categories. At webquest.sdsu.edu/searching/specialized.html you'll also find a list of specialized search sites.

A few examples: technorati.com searches blogs; newslink.org searches newspapers and magazines; earthcam.com searches for Web cameras; lib.utexas.edu/maps searches for maps -- the list goes on and on.

But TechMan's point here is that when you are searching for something on the Web, it's often good to get a second opinion. Dr. Google won't mind.

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First Published: June 22, 2008, 4:00 a.m.