Search engines utilize indexing software agent called often robots or spiders. these agent are programmed to constantly " crawl" the Web in search of updated pages. They will essentially go from URL to URL until they visited every Web site on Internet.

When visiting a Web site, an agent will record the full text of every page (home and sub-pages) whit in the site. It will then continue on to visit all external links. Following these external links is how search engines are able to find your site regardless of whether or not you register your URL with them. Submitting your URL, however, does speed up the process.It notifies an agent to visit and index your site instead of waiting for it to eventually locate you through one of your external links.

Robots will then revisit your site periodically to refresh the recorded information. The revisiting of links is the reason why some search engines don't require you to inform them of dead links. Eventually, their robot would try unsuccessfully to update the information on a dead link and realize it no longer exists.

Finally, an easy way to tell whether a Web index is search engine as opposed to another type of directory is by the information it requires when adding your URL. A true search engine will only need the Web address. The indexing agent care of the rest.

• We have about 1400 directories and search engines and we're adding about five new ones every week.
• New directories and search engines added within the past weeks are marked with the NEW! image.
• We've grouped the directories and search engines into 16 different categories.
• About 10 directories and search engines charge for listing.
• Not all directories and search engines are relevant for all Web sites. For example, some are only for non-US Web sites.
• Some directories and search engines periodically suspend submissions.
  

URLs

URL stands for Uniform Resource Locator. A URL is a standardized of accessing files on the Web. It is, in a sense, an address much like your street, city, state and ZIP code.
A URL has three parts:

• The name of the Internet service (or protocol) being used; for example: ftp, telnet, gopher, http, and so on.
  
• The domain name of the comuter to be accessed (also called a host); for example: www.star500 .com.
  
• The directory path for the file to be viewed; for example:
  http://www.star500.com/mettal.html