Chapter 27. How Internet Searching Works


An enormous amount of information is available on the Internet, but there is so little organization to the Internet that it can seem impossible to find the information or documents you want. A number of solutions have sprung up to solve the problem. Two of the most popular are indexes and search engines.

Indexes present a highly structured way to find information. They enable you to browse through information by categories, such as arts, computers, entertainment, sports, and so on. In a web browser, you click a category, and you are then presented with a series of subcategories. Under sports, for example, you'll find baseball, basketball, football, hockey, and soccer. Depending on the size of the index, several layers of subcategories might be available. When you get to the subcategory you're interested in, you are presented with a list of relevant documents. To get to those documents, you click the links to them. Yahoo! (http://www.yahoo.com/) is the largest and most popular index on the Internet. Yahoo! and other indexes also enable you to search by typing words that describe the information you're looking for. You then get a set of search resultslinks to documents that match your search. To get the information, you click a link.

Another popular way of finding information is to use search engines, also called search tools and sometimes called web crawlers or spiders. Search engines operate differently from indexes. They are essentially massive databases that cover wide swaths of the Internet. Search engines don't present information in a hierarchical fashion. Instead, you search through them as you would a database, by typing keywords that describe the information you want. (Many search engines now also include indexes as well as search tools, but they are primarily used for searching.)

For most people, Internet searching means only one siteGoogle. (For information about how Google works, see Chapter 28, "How Google Works." But, in fact there are other popular search engines as well, such as Ask.com. Although the specifics of how search sties operate differ somewhat, generally they are all composed of three parts: at least one spider, which crawls across the Internet gathering information; a database, which contains all the information the spiders gather; and a search tool, which people use to search through the database. Search engines are constantly updated to present the most up-to-date information, and they hold enormous amounts of information. Search engines extract and index information differently. Some index every word they find in a document, for example, and others index only the key 100 words in each document. Some index the size of the document; some index the title, headings, subheadings, and so on.

Additionally, each search engine returns results in a different way. Some weigh the results to show the relevance of the documents; some show the first several sentences of the document; and some show the title of the document, as well as the URL.

Each of the many Internet search engines and indexes have their own strengths and weaknesses. To cast the widest possible net when looking for information, you should search as many of them as you can. The problem is that doing so is too time-consuming. So a type of software called meta-search software has been developed. With this software, such as Copernic, you type a search on your own computer. The software then submits the search to many Internet search engines, indexes simultaneously, compiles the results for you, and then delivers the results to your computer. To visit any resulting site, just click the link, the same as if you were on an index or a search engine site.



How the Internet Works
How the Internet Works (8th Edition)
ISBN: 0789736268
EAN: 2147483647
Year: 2004
Pages: 223

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