What is a Search Engine?
A Search engine can be defined as a software program that assists a user in locating various websites or information over the internet. A web search engine is a software system that is designed to search for information on the World Wide Web. The search results are generally presented in a line of results often referred to as search engine results pages (SERPs). The information may be a mix of web pages, images, and other types of files.
Search engines are particularly helpful in locating web pages on a certain topic or in locating specific pages for which you do not know the exact URL (uniform resource locator). To find a page or pages you enter a word or phrase called search text or keyword, in the search engine text box. Many search engines use a program called spider to display a list of all web pages that contain the words or phrases you entered. It is also called a crawler or a bot. A spider reads pages on websites in order to create a catalog or index of hit.
A hit is any web page name that is listed as a result of a search. For example, If you want a listing of KFC outlet in your search text. The search engine would return a hit of web page list that contains the phrase of KFC outlet in Lagos.
When you enter search text that contain multiple keywords, the search engine usually locates a site that contains all the words. Some of the popular search websites are Alta vista, Excite, Go, Google, Mammal, ask, Msn, Yahoo!, Reddit, Look smart, Netscape search and Hot bot.
Search Method
Browsing through categories: you can browse categories such as art, science or sport to find information that interest you. When you select a category of interest a list of subcategories appears, you can continue till you get the web page that interest you.
A search engine operates in the following order:
- Web crawling
- Indexing
- Searching
Web search engines work by storing information about many web pages, which they retrieve from the HTML markup of the pages. These pages are retrieved by a Web crawler(sometimes also known as a spider) — an automated Web crawler which follows every link on the site. The site owner can exclude specific pages by using robots.txt.
The search engine then analyzes the contents of each page to determine how it should be indexed (for example, words can be extracted from the titles, page content, headings, or special fields called meta tags). Data about web pages are stored in an index database for use in later queries. A query from a user can be a single word. The index helps find information relating to the query as quickly as possible. Some search engines, such as Google, store all or part of the source page (referred to as a cache) as well as information about the web pages, whereas others, such as Alta Vista, store every word of every page they find.
Search by Keyword
You can type a word in a search tool about a web page of your interest. The search tool will display a list of webpages containing the word you specified. Some tools allow you to enter a complete question when searching for web pages.
List of Search Engines according to categories
General – Google, Soso.com, Yahoo! and Bing
Metasearch (A metasearch engine (or aggregator) is a search tool that uses another search engine’s data to produce their own results from the Internet.) – Info.com, Mamma, Metacrawler, Excite.
Business – Business.com, Genieknows
Education – Noodle Education, Skilledup
Fashion – Fashion Net
Medical – Bing health, WebMD
News – Yahoo! News, Google News, Bing News
Video games – Wazap
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