A search engine is a computer program that uses an algorithm to find information requested by a user on the World Wide Web. Some of the more popular search engines include Google, Yahoo, MSN, and Ask Jeeves.

How a Search Engine Works:

When a user goes to a search engine to look for specific information, the user enters a word or phrase, also known as keywords. When the user hits the "search" icon, it triggers the search engine to begin a query to locate web pages that are most to the given search criteria.

The search engine sifts through its database of web pages, and displays the results that most relevant to the given criteria. Most search engines also rank results by relevance to the search criteria provided.

Since search engines need to return the results relatively quickly, they do not search the World Wide Web every time a query is initiated. Instead, search engines have a database of web pages known as an index. Search engines update this index every few months by initiating their spiders, an automated program that visits (or crawls) and stores web pages currently in their index as well as pages that users have submitted since the last crawl.

Spider Food:

There are several factors used by a search engine to determine the ranking of each web page shown in the results for a particular query. The most important factor is the usage of keywords in key areas including:

Metatags: Metatags are used in the beginning of the HTML source code and are commonly used to identify the keywords and description of the webpage, as well as many other things such as the author, page title, date of creation, and subject that are not directly visible on the webpage.

Page Title: The page title appears at the very top of the window of the web browser. It is not part of the content of the actual web page.

Page Header: The page header is brief, textual information about the body content.

Body Content: The body content is the actual text on the webpage.

Inbound Links: The inbound links are external websites that point at to a particular website

Alternate Text: While flashy graphics and bold colors are important to catch the eye of your viewer, it is important to know that a search engine cannot decipher what an image represents. Since a search engine cannot "read" a graphic, it is important to incorporate text into the HTML coding (Alternative Text) to tell the search engine (as well as visually impaired users) the function of the image.

Summary:

When creating or updating your website it is important to remember to design your page for the end-user, but remember to incorporate the important information relevant for a search engine. Also provide titles for your graphics and insert alternative text appropriately, so that they match the overall objective and content of your website. Lastly, ensure that page titles and headings reflect the targeted keywords relevant to the content that the user will find on the page.