How the www.Google.com Search Engine Works and one Advantage and Disadvantage in this Method of Searching

b) Search Engine databases are selected and built by computer robot program called spiders. They crawl in the web in their hunt for pages linked to other sites. They find the pages for potential inclusion by following the links in the pages they already have in their database. After the spiders find pages, they pass them on to another computer program for ‘indexing’. This program identifies the text links and other content in the page and store it in the search engine database’s files so that the database can be searched by keyword and whatever more advanced approaches are offered, and the page will be found if your search matches its content and rank them in order with the best result at the top or most relevant.

ADVANTAGE- It is much better than other search engines at determining if a link is a true editorial citation or an artificial link.
It is more efficient in crawling than competing engines.

DISADVANTAGE- It covers a relatively small proportion of the static web pages. The indexes can be significantly out of date, they do not search, they generally do not search the vast numbers of pages in the invisible web and can fail to provide sophisticate search when the user has a specialised category or topic of search in mind.

C) The search engine I would prefer to use when searching the web is Yahoo, because unlike Google it gives information to a great extent, to the sub-heading hence being able to locate the site that covers the area which I was looking, and the same time I get to learn more information.

REFERENCES:

Sullivan, Danny.(Mar.14.2007).How search engines work. [Online]. Search Engine Watch.Available from:http://searchenginewatch.com/showPage.html?page=2168031 [Accessed 07/10/07].

Barlow, Linda.(updated 05/11/04).The spider’s apprentice.[Online]. Monash.Available from: http://www.monash.com/spidap3.html [Accessed 07/10/07].

Wall, Aaron.(2007).Search Engine History. [Online]. Search Engine History.Available from:
http://searchenginehistory.com/ [Accessed 07/10/07].

HOW THE www.Yahoo.com SEARCH ENGINE WORKS AND ONE ADVANTAGE AND DISADVANTAGE IN THIS METHOD OF SEARCHING

SEARCH ENGINE- It is a program that searches a document for specified keywords and return a list of the documents where the keywords were found. It works by sending out a spider to fetch as many documents as possible.


Yahoo is the web's oldest 'directory' where human editors organize web sites into categories.It has both human-edited directory and a spider based index provided by Google. Sponsored results are provided by overture and appear at the top of the results page and additional entries are presented at the bottom of the page whenever a next page is available. It classifies information under a series of major subject headings and then sub-dividing these into a more specific headings. The web sites that correspond to these headings are listed as appropriate in this directory structure.


ADVANTAGE- It is excellent and easy to navigate subject catalogue. The subject heading and sub-headings can be used to guide the user through vast amount of information until they find what they are looking for.


DISADVANTAGE- Directories are far more cost and time intensive to maintain due to lack of scalability and the necessary human input to create such list and periodically check the quality of the listed websites.
Unlike highly automated search engines, Directories are manually complied taxonomies of websites.

References:
Sullivan,Danny.(Mar.14.2007).How Search Engine works .[Online].Search Engine Watch. Available from:
http://searchenginewatch.com/showPage.html?page=2168031 [Accessed 07/10/07].

Barlow,Linda.(updated 05/11/04).The Spider's Apprentice. [Online]. Monash.Available from:
http://www.monash.com/spidap3.html [Accessed 07/10/07].