Search Engines

Search engines are the work horses of internet searching.

Search engines scour the web at large. This is in contrast to article databases, such as EbscoHost or Infotrac, which search within collections of previously published magazine, journal or news press articles or broadcast transcripts. Article databases offer the added benefit that some degree of editorial control and fact-checking has been done on the included materials. Materials located using search engines offer no such guarantees.
Site-specific search engines help users find information within a web site.
Metasearch engines take a search term(s) and run it simultaneously through several search engines. Depending upon which metasearch engine you use, you can select search engines, how many results are displayed, and see how the keyword search was sent to the different search engines.

Common Misconceptions about Search Engines

Search engines do NOT search the entire web. They only see about 1/500th of the web's current content. The rest is "invisible" to search engines because it is database content, active server pages, pages that require registration by a user, specialized file types, or even the content of extra long web pages that exceed the parts of the pages assessed by search engines. Most of this "invisible web" content is free to any user and of higher quality than the majority of resources available on the "surface" or part of the web searched by search engines.
Search engines do NOT go out and "search the web". They search a database constructed from the parsed content of web pages that have been examined by programs called spiders. These databases are not refreshed daily or weekly, but over time, with more highly ranked pages and certain types of pages being re-checked much more frequently than other sites. News site content, for example, is reassessed several times a day.
Search engines do NOT find the same results for the same search request and do not rank results that they do find in common the same way. This is because search results are produced as a result of complex calculations of many factors, and these calculations are the patented technology that makes each engine unique. It is for this reason that using multiple search engines is important.
Search engines DO sell listings in results, called "sponsored results". These show up as a part of a search because some advertiser paid for them to be there when particular keywords were searched, not because they are the best result for a given search.
Search engines DO have many different kinds of special searches and techniques that improve your chances of finding good search results.

A short list of search engines.

Rather than try to list every search engine, this list contains several that the library staff either recommends or knows many users are familiar with, along with brief comments.

Ask		Recommended. Ask.com combines the former AskJeeves.com answer service and metasearch utility with Teoma's search technology to create a unique database and set of search tools. The variety of search resources is quite useful, and the search results are presented along with useful suggestions about how to narrow or broaden your search. Unfortunately Ask gives too much prominence to paid search results, often turning over as much as 1/3 of a page to these.
Google		Strongly Recommended. The current king of search engines, Google's search spiders look at more of the web, provide cached (saved) copies of results from their own scans, and furnish excellent image and alternative file format searching. Google also offers a directory search option. It does not, however, search entire web pages, but only the first 101K of each. It's coverage is also not as comprehensive as many believe. Its tools and additional search options, however, make it the premier tool in the field. Check out Google Books, Google Scholar, U.S. Government search and Google Labs to see the variety of search features that are available.
Yahoo		Strongly Recommended. Premiered its own search engine database in February 2004. Its content range is impressive and benefits from links to its directory. It includes a cache feature. It also offers a wide range of different specialized search possibilities. Sponsored sites (paid position results) now appear at the side and bottom and are much easier to distinguish. Yahoo has done a good job of simplifying its front page while maintaining access to its many services. An alternate search only page can be found at http://search.yahoo.com Yahoo does not search entire web pages, but does search a larger portion of their content than Google does, topping out at 500KB.
Live Search		Recommended. Live Search is the replacement to MSN Search. Unlike its predecessor, it draws on its own unique database, making it a useful tool to combine with Google, Yahoo or Ask. It has a simple interface, but is limited by the fact that the only way to access Advanced Search features is to run a basic search first. Live is also hampered by the 10 word limit imposed on search strings, which can interfere with searchers who tend to use natural language rather than keywords or who opt for very long keyword strings. Its cache does, however, date when pages were recorded, a potentially very useful feature.
AltaVista, AlltheWeb, Excite, Go, Infoseek, Teoma		Dead but not gone, these search engines still exist but are "covers" for other search engine technology and no longer have individual search profiles.
AOL		Not Recommended. AOL relies largely on Google for its search results, resulting in considerable overlap. What doesn't overlap often leans towards commercial sites.
Exalead		Recommended. Nifty new entry into the search engine field. This one frequently does not overlap Google's results. This one includes a thumbnail of the web page next to the result and related categories to help users refine their searches. Users can adjust display options to the degree of additional information they wish to have displayed at the original search. Links next to results let users quickly narrow down by location and document type as well, all without having to switch to advanced searching. Opening a link originally opens it in a new frame, but a button makes it easy to open the link in a new browser window. The greatest weakness of this search engine is the relatively smaller portion of the web that it covers than the larger search engines.
Wisenut		Recommended. Although this search engine relies on a smaller database and has more limited searching option than others, it does offer a unique set of results and a useful set of suggestions to refine a search that come up when a search is run.

If you'd like to know more, check out these sites:

Search Engine Showdown Reviews — Greg R. Notess' careful analyses of the constantly changing world search engines. Included among the site's features is a useful chart comparing the features of various search engines.

Search Engine Watch — Danny Sullivan and Chris Sherman's website devoted to the the ongoing analysis of search engines. These two sites are the place to check for up-to-date information on search technology.

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