6 Facts About How Search Engines Work
Although the technology behind each search engine varies slightly, there are some basic things you can learn about how search engines work that can help you improve your search skills.
Search engines are online software programs designed to help users locate relevant Web sites or articles. Understanding how search engines work can help you get the results you want and sort through the irrelevant, misleading results you’ll undoubtedly encounter.
Six basic things to know about how search engines work:
1. When you enter a term into a search engine, you're not searching the entire Web. Rather, you're searching the Web sites that the search engine has indexed. If the search engine hasn't added a Web site to its index, it cannot include it in the search results.
2. Spiders are powerful but they can travel only through the hyperlinks that connect Web sites. If a page isn't linked to any other pages, spiders can't find it. Also, search engines work best with sites that cooperate with search engines by creating a “site map” that tells a search engine where to spider. Many sites don’t do this.
3. The part of the World Wide Web that is not linked to other sites is called the "invisible Web" or the "deep Web." It may contain information highly relevant to your search.
4. Search engines don't know why you want information—they find information they deem relevant to the words you've entered. These results are not recommendations; search engines don't rank their results by the content of each site. They use mathematical equations algorithms to rank them, and the formula may have little to do with a site's credibility or relevance to your task.
5. Companies have gotten wise to the way that search engines work. Many Web pages are created and customized with the goal of appearing near the top of a search engine’s results list regardless of their credibility or usefulness. This practice is called "search engine optimization," and to it's one reason that not all of your search results will be relevant or trustworthy.
6. The "Help," "About" or "Preferences" sections of a search engine site have helpful tips for using that particular search engine to your advantage. For example, if you’re looking for a definition, Google tells you to add “define:” to the beginning of your keyword. Thus, a search for “define: search engine” in Google will give you a list of definitions for “search engine” from around the Web. Similar tricks are innumerable, and all search engines have them. Google has a complete list of “search operators.”