How Does Google Work?
A Simple Explanation.
What happens when you make a Google search?
Firstly, when you make a Google search, it doesn't search the web, it searches Google's index of the web. These are two very different things. On every page there are links; spiders (or web crawlers) search the web, and follow the links on the web until Google has a pretty big chunk of the internet. This is Google's index of the web. If a web-page has no links to it, then Google cannot find your page!
What happens next?
When you make your query on Google, say you searched, 'Cheetah running speed', it searches all of the pages on its index. Then how does Google chose between these millions of web pages? Through questions- over 200 of them! These can include- When on the page does it say, 'Cheetah running speed?' At the top? On an advert? How many times does it say these words? These questions are immensely important because otherwise you would get pointless webpages that may only use one of these words for something completely irrelevant to what you are looking for.
The Page Rank System
The Page Rank System is a system invented by Larry Page to find out the importance of different sites and web pages, to see if they were worthy of your viewing. When a certain page is selected, one of the questions is, 'How important are the pages that put the link to that page on there?' This is an ingenious system that works in less than half a second. If you want to find out more, click the link- http://en.wikipedia.org/wiki/PageRank
So, after all this, after all the questions are asked and everything on Google's index had been searched you get your results back. How long did all this take? Less than half a second.