Finding Information on the Web

About Search Engines

Search engines allow you to perform keyword searches for Internet sources. Search engines send "spiders" through the Web, which compile information on what is available and load that information onto the search engine's database. You can then search these databases to find sites that match your keywords. Note that this means you are not searching the Web itself, but only as much of the Web as the search engine has been able to copy, and some of their links will likely be out of date. Search engines are useful if you are doing a thorough search of as many Internet sources you can find on a topic, if you are researching a narrow or specific topic, or if you just want to quickly find a page or two relevant to your topic. Keep in mind that search engines can find a lot of information, but they cannot evaluate its reliability or accuracy. 

Often, you will get thousands of results from a search. That does not mean you have to sift through all the results to find the most relevant ones. If you structure your search statements well (see the Searching Indexes and Databases section of the Research Skills Tutorial), search engines usually do a good job of putting the most relevant sites near the top of the list. They use various strategies for determining relevance: how often your search terms show up on a page, where they appear on a page (title or first sentences have more weight), or even how many other pages link to a page. But note that some search engines are now selling priority in search results, so some of the top results may be there because advertisers paid to be listed first. And even without selling priority, these strategies of determining relevance are purely mechanical, and so are only an estimation of relevance. 

When using search engines, keep in mind: 

• No search engine is perfect.
• None of the databases contains ALL the documents on the Internet. Even if you have a favorite search engine, use more than one if you are doing a thorough search. Each will likely find things that others missed. 
• Search engines use different criteria to determine a relevancy rating of each hit. The most relevant hits for your purposes may or may not appear in the first few screens, and different engines will list different sites among their top results.
• Even using many search engines will miss much that is available on the Internet but inaccessible to search engines. See the Invisible Web and Subject Directories sections. 
• All search engines have a help page. This is the first place to visit when trying a new search engine.
• Every search engine is different. They all have syntax that must be followed for an effective search.
• Beware of the default Boolean logic. For example, Alta Vista defaults to OR. If you want to use AND as the Boolean operator you need to type a plus sign (+) in front of each search term. 
• Search engines are constantly updated and new search engines developed. Check out the Search Engine Watch or the Search Engine Showdown for the latest, as well as for more information on how search engines work. 

Getting the most out of search engines: (See search engines' help screens to find out how to do these tasks with each engine)

• Use several terms to describe your search. Most people use only one or two terms in most of their searches on search engines. Using more terms tends to make the results more precise (i.e. fewer irrelevant results). 

• Use Boolean logic with your terms, i.e. combine terms with AND, OR, and NOT and parentheses for increased precision. Each search engine works differently, so check their help screens. 

• Use truncation (also called wildcards) to find variant endings of a root, e.g. "comput*" finds computers, computing, computation, etc. Check each search engine's help screen to see whether and how truncation works on that engine. 

• Use quotes around a phrase, e.g. "United Nations Population Fund" will find only pages that have that exact phrase rather than pages that have all the words in any order somewhere on the page. 

• Use the Advanced Search features available on most search engines. These usually include the ability to: 

  • Restrict your search to education (.edu), government (.gov), or other domains. 

  • Limit your search to the pages at one Web site (e.g. www.wesleyan.edu) 

  • Look just for pages with images, sounds, .gif files, MP3 files, or other specified media or formats. 

  • Restrict your search to recently created or updated pages. 

Major Search Engines

Here's a list of some of the major and most popular search engines, with a note or two about special features. See the Search Engine Watch or the Search Engine Showdown for more specifics about each, and for more search engines than listed here. 

Specialized Search Engines

There are two main types of specialized search engines: metasearch (or multithread) and specialized: 

Metasearch engines search many regular search engines simultaneously. They are useful when you want to retrieve as many sites as possible with one search (though often they only return the top portion of results from each search engine). They are especially good for searching obscure topics. Their drawback is that they are only effective with simple searches, since advanced features such as Boolean and truncation are done differently by different search engines. Here's a list of some of the major metasearch engines (see the Search Engine Watch for more): 

Specialized search engines are available for some specific topics or types of resources. Here is a list of some. Subject directories are often good sources for finding subject specific search engines. The Search Engine Watch also lists more.  

Next: Subject Directories     

Contents - Internet - Searching - Search Engines - Subject Directories
Invisible Web - Listservs and Newsgroups - Evaluating - Citing