By using these search tools you can quickly find those resources or products that are relevant to you. Search Engines get their name from the software that searches through the indexed databases it creates. These indexes are special Web documents which can be searched rather than read. The results of such a search are displayed in another Web document containing links to the documents found. A Spider, the Index, and the Search Software.
Most engines run several spiders that explore the Web as a team.
The crawler looks for new Web pages or changes in existing ones to place in it's catalog. The number of Web pages visited and how often varies from engine to engine, but the typical crawler visits several million Web pages a week. The Search part of the engine is software that allows you to look for pages containing information in response to one or more key search words that you have entered related to what you are looking for. Any given search usually results in several hundred to several hundred-thousand possible relevant Web homepage that matches your search inquiry. If this sounds complicated it's really not.