A search engine is technically a program which functions much like a card catalog that indexes and locates a users query (desired information) from a database of Internet resources. There are two kinds of search engines. The crawler-based search engines generate their listings robotically by crawling or spidering the Web. One good example of this type of site is Google. Human-powered directories, on the other hand, depend on site owners or managers submission of short descriptions to the directory.

History

The earliest form of search engine was invented in 1990 by Alan Emtage. He called his program Archie, which is actually short for the word archives. It was much simpler than todays search engines it simply downloaded directory listings of every one of the files positioned in public nameless file transfer protocol (FTP) sites, and made the list into a filename database that can be searched.

Significant changes happened three years later when Matthew Gray from MIT fashioned the first Web robot, which he aptly named the World Wide Web Wanderer. The initial purpose of the Wanderer was simple it was designed just to compute for how big the internet is by counting servers. After a short while, the Wanderer was applied for URL generation and formation of the worlds first Web database, aptly called the Wandex.

More programs soon followed suit, but it was only a year later (in 1994) when Yahoo! was launched by partners Jerry Yang and David Filo. Yahoo! started out as a directory it was simply a list of the partners preferred sites. The search results contained both a sites the URL and a brief description of the page. Yahoo! switched to more high-technology practices when it was incorporated in the latter part of the same year.

Many other search engines started to become popular. Around the same time, WebCrawler and Lycos were launched. These sites made important headways in terms of relevance retrieval, word proximity, and prefix matching. But it was not until 1995 that natural language inquires and innovative searching techniques stared to be supported by Alta Vista. Finally, Sergey Brin and Larry Page launched Google in 1997 and the face of search engine ranking changed forever.