The Search Engine collects a database of information about document on the web. The search engine then allows the users to look for particular words in the database, and it returns links to the documents that contain the users search items. If the user selects his search items effectively, he will be able to find web pages relevant to his topic of interest.
When the user first seeks the information, the user can invoke an automated search for the topic. The search tool produces a list of candidate pages that may contain information of interest. The user reviews each page in the list to see whether the contents are relevant and interesting. If so, the user records the location; if not, the user simply moves to another page in the list.
In short we can say since the internet is vast, finding information on a given topic can be difficult. Search engines help users by finding a set of pages that contains information related to the topic.
Every search engine uses a crawler or spider with its specific set of rules pointing that how documents are gathered over the web. Several go with each link on all home pages they locate and next scrutinize every link of new home pages consequently. Some spiders take no notice of links that directs to animation files and graphics files.
As the spider discovers documents and URLs, software agents are instructed to get the URLs and documents and send information to their indexing software.
The indexing software obtains the URLs and documents from the agent. The software takes out the information from the stored documents and indexes it. Every search engine takes out and indexes various types of information. Some index every word in each document, but others index only the key 100 words in each; some indexes the size of the document and the number of words in it; some index the title, headings and sub heading, and so on. The kind of index built will determine what kind of search can be done with search engines and how the information will be displayed.
When the user visits a search engine and want to search the internet for information, he will type words on a web page that describe the information he wants to find. Depending on the search engine, more than just keyword scan can be used. For example, we can search by date and another criterion with some search engines.
When the user clicks a link to one of the documents that interest him, he is sent straight to that document. The document itself is not in the database or on the search engine site.