There are three major pillars, Google rely on while indexing WebPages
Bots and Crawlers: Huge set of programs used to fetch or crawl billions of web pages and automatically following all of the links on each web page.
Indexers: A program that analyzes web pages downloaded by the spider and the crawlers.
Servers: For interacting between the user and the search engines.
Googlebots (also known as robot, bots or spiders) are set of programs to fetch up billions of web pages. Bots are software built to go through every page of a website, categorize them and place them into the Google database. Googlebots have their specific algorithms which determine how many pages to fetch from a website.
Google has three well known bots: The Adsense bot, the Freshbot and the DeepCrawl. Adsense bot is generally used for publishers having Adsense on their website. Whenever a new page is created JavaScript within the address code sends a message to the Adsense bot and pages are reviewed by bot within 15 minutes.
Freshbots only use to crawl the most popular pages on a website. Such pages can be one or even thousand. Generally freshbots visit a typical website within 1 to 15 days; it usually depends upon the popularity of the website. Some very popular websites like Amazon.com receives fresh bot crawls in every 10 minute. The credit goes to regular updating and frequent changes in the websites. Freshbot finds all the deeper links in your website and collect those links in the database.
Deepcrawl bot visit a website once per month, and crawl over all the links referenced by the freshbot. Though deep crawl occurs only once in a month it takes up to a month for your entire site to be indexed in Google. Even if you submit Google sitemap your website you have to wait for a deep crawl to occur.
Google likes fresh content and if you can get genuine valuable inbound links for your website Google will definitely fall in love with your website. Website architecture is an important aspect when it comes to best SEO practices. Read out the complete Google webmasters guidelines to generate more traffic for your website and to rank higher in Google with a better PR.
Summary: Google bots work 24X7 and remain hidden from the world. Indexing of WebPages by Google is not a wonder; bots are the real workers behind it. Google has three different bots namely- freshbot, Adsense bot and Deep crawler. These bots crawl each and every web page on the internet and fetch the pages which qualify Google’s criteria of displaying relevant web results.
About Author:
Tarun Gupta is Employer of the Professional SEO Company which offers replete SEO India Services to move away optimization activities successfully.



