The document discusses the history and workings of search engines. It describes how search engines like Archie were some of the earliest examples from 1990. It explains the process search engines use, including crawling the web with bots, indexing pages, and then processing queries to return relevant results. The document also discusses the importance of search engine algorithms and why they are kept secret by companies. Finally, it briefly describes Google's new Caffeine search engine and Yahoo's BOSS platform that allows developers to build custom search tools using Yahoo's index and infrastructure.