Googlebot

Google's web crawling robot (or spider) is Googlebot. Like other search bots, Googlebot's key functions include finding and requesting webpages, downloading the pages to a server, then sending the downloaded pages to an indexer. Google's indexer will then categorize and sort each word on a webpage (ignoring the pictures and graphics), and put all this information on a massive computer database. This database is used by the query processor, which takes a search term query you type in, compares it with the database that has categorized every word on the internet, and gives you a list of search engine results.

Googlebot works much faster than a typical computer can work, and can multitask much more efficiently. They rapidly crawl through millions of pages of text, following links when necessary. Googlebots are actually a massive number of computers at Google whose sole function is crawling. Googlebots crawl through all websites on the Internet to help indexing computers index new pages, make sure links still are good, and they check for updated URLs and other site changes. Google's Googlebots (separate from Google AdWords) work to maintain impartiality; Googlebots crawl through all sites as equally as possible (although given the fact that some sites are built to be more search-engine friendly, obviously some sites get noticed more than others).