There are many types of search tools available on the Web. The most common are search engines, directories, and metasearch engines:

Search Engines. When you use a search engine you aren't searching the entire Web as it exists at the particular moment in time. Instead, they allow you to perform keyword searches of large indexes of Web sites compiled (and continually updated) by each engine through the use of electronic 'spiders' (also called 'robots' and 'crawlers') that crawl through the millions of Web pages at sites around the world. Search engines are useful  for finding everything on a subject, for very precise searches, or for esoteric or obscure topics.Recommended Search Engines.

Directories. Also called guides or indexes, directories are compiliations of Web sites that have been gathered, reviewed, and organized by human indexers. In most cases, the search engines you'll find at these sites will allow you to search the directory and not the Web at large. There are some search engines that also include directories or indexes and function as a sort of hybrid of both types of services. Yahoo is the most popular example of a Web directory. Directories are useful for finding popular sites (White House, Green Bay Packers, Disney), for times when you don't have an exact search in mind and want to browse sites in a particular category, or when a search engine returns too many irrelevant sites. Recommended Directories & Guides.

Metasearch Engines. These resources allow you to search multiple individual search engines simultaneously. Results are usually returned either arranged by search engine or integrated into a single set. The best metasearch engines will also eliminate duplicates. Some metasearch engines function as lists of search engines and allow you to search for subject-specific search engines. Metasearch engines are useful when you want to find as much as you can on a topic and don't want to search each engine individually. Recommended Metasearch Engines.

The Web isn't arranged like a library and search engines don't function like the library online catalog with which most of you are familiar. There is no controlled vocabulary or subject headings assigned to Web pages that search engines use when conducting a search.  Since search engines work by using simple keyword searching, think carefully about the best words that will describe exactly what you're looking to find.

None of the search engines in existence indexes the entire Web. The size of the Web is too vast and changes too frequently for any one engine to index its entire contents. For the most comprehensive results, try your search in more than one search engine. You can also try using a metasearch engine which allows you to search multiple engines in one search. 

Each engine varies slightly in the method used to compile its index, rank results, and how often sites are revisited. Depending upon how long it has been since an engine revisited a site, some of the search results you get may contain non-working links. Precise information about the methodology each site uses to search its index is proprietary, but you can get a good general overview of how each search engine works at Search Engine Watch.

Learn the search syntax used by the search engine you are using. Many times, typing a bunch of words into the search box will retrieve an overwhelming number of results, or too many that are irrelevant to your needs. Taking 10-15 minutes to learn everything you can about the search engine can save you hours of frustration. Remember to think carefully about what you're trying to find and try to construct the narrowest search you can. More on Search Syntax.

Most search engines have a list of 'stop words', words which occur so frequently in their index that they are disregarded in a search. Often 'stop words' are obvious: the, an, or. They often include words related to the Internet: Web, WWW, Internet. Some search engines provide a list of 'stop words' but others, such as Hotbot, have an ever-changing list of words, depending upon the frequency of a particular word in the index. For example, Hotbot's list recently included the word 'date'. Unfortunately, this made a search for 'date rape' reveal the same number of results as searching for 'rape' because date was tossed out as a 'stop word'. If you get odd results from a search, it could be that one of your words was on the 'stop word' list for that particular engine, so try your search in another search engine.

Most search engines provide advanced search features and forms that allow you to construct more complex searches.  You can often do a much better search by using these advanced features. Typically, you can find out more information about them by searching the help files or clicking on a button that says something like "Advanced".

If you still can't find something, it may be that the particular resource you seek isn't available on the Internet. There is much more information that is not available on the Web than people realize. Remember that most scholarly research, particularly academic, refereed research articles, are not freely available on the Web and you might need to use a print or journal or article database to find this information. Here, on the MU Libraries' website you'll find a page of Research Sources that lists indexes available to Marquette users via our Web site and within the Libraries.

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