Search Engine and its Classification

Search Engine

Search engine is set of programs or a software system that enable user for search  information or document available on World wide Web according to search term     or Keywords . Google ,Yahoo ,Bing 

Crawler Based Search Engine

Web crawler or spider is automated software that browses World Wide Web and read content available on web pages and follow link from one page to another page with the help of link, spider can reach billions on interconnected webpages.Crawler based search engine uses web crawler or spider to index web pages or its content and link according to relevance keywords

Google and Yahoo is Crawler based Search Engines

Human Powered directory

 This type of Search engine do not use crawler or spider to update and indexing in their data base these type of search engine Depend on human editors to create their listings. Manually we can submit description about a website and we can choose a category and submit website in these types of search engines example open directory and  yahoo directory

Hybrid Search Engine

Hybrid search engine-this type of search engines provide search results with the help of crawler and directory most of the search engines now going to be hybrid Google is now hybrid search engine

Meta Search Engines

When this type of search engines receive user request of keywords than request send to other search engines or database and combine the results into single list for display meta search engines create virtual data base they receive user request and send it to some other data base and give the results