1. Crawler-based search engines
Crawler-based search engines ( Google, Yahoo, Bing ), Those web sites are creating the list of information that we are searching.
- – The web server will send the query to the server. the context in the server is almost the same with the server in the back of the book. It will show you the words that match with the query
- -the doc server will get the query and the information will explain each search result.
- -lastly, the search results will send back to the user in a second.
2. Human-Powered directories
Human-powered directory, the quality of this kind of search tools are depend on the humans for its listins. the writer will submit the information. It is include to the directory for the entire site.Descriptions submitted is the only thing that the search looks for matches, so changing web pages has no effect on how the writer are listed.
the way to improve a listing in a directory is that they must have a good content because the techniques has nothing to improve a listing in a directory. It might be better to get a review for free than a poor site.
3. Mega-search engines
Mega-search engines, such as Mamma, Metacrawler and Dogpile. Mega-search engines, it is good for saving the time because it is better to use this option in one place and sparing the need to use and learn several seperate search engines. It will be better to use to find hits on obcure items or something that can be found by using the internet
References
1. http://www.yuanlei.com/studies/articles/is567-searchengine/page2.htm
2.http://threes.com/index.php?option=com_content&view=article&id=2560:three-types-of-search-engines-&catid=68:business-economics&Itemid=47
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