Search Engines

Unlike subject directories, search engines do not use people to collect web pages. Search engines are mostly computer automated programs that allow you to search for information on the WWW.

A search engines starts out with a computer program that is often generically called a spider. A spider will start with a web page and follow every link on that page. Then it will follow all the links on those pages and the links on all the pages it finds after that. For every page the search engine visits, it collects some or all of the information on that page. The search engines we will look at collect all the information on every page they visit. That information (which is mostly just the words that appear on the page) is then put into a large index of words that appear on web pages. So an index from a search engine is a lot like an index in a book, except that a search engine indexes all the words (or almost all) that it comes across.