a search engine is an information retrieval system designed to help find information stored over WWW. complex search engines help to minimize the time taken to find information and increases the quality and accuracy of particular information we retrieve.
following is a list of popular web sites currently available:
google.com
yahoo.com
live.com
ask.com
earlier days all search engines were based on HTML meta tags for keywords. so the search results were mathed based on the keywords found in that article matched with the search query. but as the no of web pages which get published in the internet doubled day by day the search results had millions of pages and the relevancy of the particular search result and the initial search query was much lower.
to address the previously mentioned problem a new technology called "Semantic Searching" was introduced. the main idea behind this was to give user of the search engine more relative information based on the search query. nowadays semantic web is being promoted by the usage of RDF or DC for every web page. but as no one can force all the web pages in the world wide web to associate with RDF the assurance of true semantic web is far away from today itself.
the next big topic about search engines is to know how to make the web pages being created to be search engine friendly. this process is named as "Search Engine Optimization". while following SEO process you can make a given web page's visibility towards search engines to increase, thus giving it a higher rank among other results. there are two ways in which you can achieve this. either you can follow "white hat SEO" or either you can use "black hat SEO". with white hat SEO it might take more time/cost to achieve the task of a higher ranking but the output tends to be consistent over time. but in contrast if you follow black hat SEO your web site can get black-listed or banned forever from search engines which results in bad reputation for the brand you promote.
