How do search engines get results?
To find results, search engines follow an algorithm to produce a set of results based on the keyword or phrase you enter. For example, an engine might index a website according to the number of times that the word appears on a page. The engine might assign a weight to each entry, with increasing values assigned to words as they appear near the top of the document, in sub-headings, in links, in the meta tags or in the title of the page. Each commercial search engine has a different formula for assigning weight to the words in its index. This is one of the reasons that a search for the same word on different search engines will produce different lists, with the pages presented in different orders.
Search engines, like Google, do not evaluate the accuracy or value of the websites, and there are sites that contain inaccurate, out-of-date, and even false information.
There are many different types of information available online, but most webpages can be categorized into one (or more) of five basic types:
Business or marketing pages are usually published by companies or other commercial enterprises.
Their primary purpose is to promote the company or to sell products. Business and marketing pages often include a mixture of information, entertainment, and advertisements.
Examples include:
For U.S. based sites, the URL or web address usually ends in .com
For international-based sites, the URL or web address often ends in .co.** (** is the two letter country extension).
News and current events sites provide extremely up-to-date information, and include news centers, newspapers, and other periodicals.
Some news and current events sites may only provide a limited amount of free information–a few days worth to a few weeks worth– and/or may require registration.
Examples include:
Informational pages provide factual information on a particular topic.
Informational pages are often provided by government (.gov) or educational institutions (.edu) and may include reference materials, research reports, databases, calendars of events, statistics, etc.
Examples include:
Advocacy pages are usually published by an organization with the purpose of influencing public opinion.
The URL address of an advocacy webpage frequently ends in .org (organization).
Examples include:
Personal pages are published by individuals who may or may not be part of a larger group or organization.
Personal webpages may include almost any type of information including biographical data, information on work, hobbies, etc.
Examples include individual or family home pages, individual faculty or students at a university, and member pages from an Internet Service Provider.
The website may contain a tilde (~) or percent sign (%) in the URL.