According to Netcraft, the Web statistics organization, the Internet hosts over 625 million active websites as of the time of publication. Search engines such as Google and Bing are the keys to finding the answers you seek in this huge mass of data. A search engine surveys sites and builds a database organized according to their content. When you type a few descriptive words in the search engine's home page, it finds and displays a list of matching sites ranked by relevance.
A search engine saves you time in two ways: by eliminating the need to find information manually, and by performing searches at high speeds. Without a search engine, you would have to look at sites one by one and pore over the contents of each carefully – a tedious prospect. A search site automatically compares your criteria to billions of Web pages and gives you results in a fraction of a second. You can perform dozens of searches in the course of a few minutes, altering the criteria as you narrow down results.
When a search engine scans a website, it scores the content for relevance to particular search words. For example, the site, "Joe's Pizza" scores higher for the search term "pizza restaurant" than the site "Acme Pizza Dough Distributors." Although search companies keep their ranking formulas secret, they take into consideration factors such as repetition of related words and links from other sites. A search engine sorts its results page by relevance to your criteria, with the score in descending order. You see the highest-scoring results at the top; as you move down the list, websites become less relevant.
Some search engines, such as LexisNexis, specialize in legal or other specialized, scholarly information; these sites charge a fee to use their services. Google, Bing and Yahoo pay for their operations through advertising; searches are free to the user, without restrictions for the information you seek, the time spent on the site or the number of searches you perform. Although this benefits all users, it is a particular advantage for students, job seekers and others of limited means.
Search engines scan the entire Web and keep comprehensive data on every page they catalog. Because search companies hold so much data, they help you find obscure sites about which you would not otherwise know. Search results are more likely to give you too much information rather than too little.
In addition to keywords, search engines let you use advanced search options to refine your results. These options help make your searches more flexible and sophisticated. For example, to exclude results containing a certain word, type a minus sign before the word. To look for an exact phrase, surround it with quotation marks. When you want to search only a specific site or group of sites, type "site:" without quotes followed by the site's Web address. You can, for example, search for mentions of beer on Facebook by typing, "beer site:www.facebook.com." To search all college and university sites for nuclear physics, use, "nuclear physics site:.edu."
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