Google uses automated programs called spiders or crawlers, just like most search engines. Also like other search engines, Google has a large index of keywords and where those words can be found.
A Web page's PageRank depends on a few factors:
How long the Web page has existed: People create new Web pages every day, and not all of them stick around for long. Google places more value on pages with an established history.
Out of these three factors, the third is the most important. It's easier to understand it with an example. Let's look at a search for the terms "Planet Earth."
As more Web pages link to Discovery's Planet Earth page, the Discovery page's rank increases.
Because Google looks at links to a Web page as a vote, it's not easy to cheat the system.
Google initiated an experiment with its search engine in 2008.
Google offers many different kinds of services in addition to chat. In the next section, we'll see how some of them work.
What are Google Spider bots?
Googlebot is Google’s net crawling robot, which finds and retrieves internet pages on the web and gives it to Google indexer.