What is a Search Engine ?

Basically, a search engine is a software program that searches for sites based on the words that you designate as search terms. Search engines look through their own databases of information in order to find what it is that you are looking for.The term "search engine" often is used interchangeably. Search engines automatically create web site listings by using spiders that "crawl" web pages, index their information, and optimally follows that site's links to other pages. Spiders return to already-crawled sites on a pretty regular basis in order to check for updates or changes, and everything that these spiders find goes into the search engine database.