Think like Google - How Google works

How Google works covers Google hardware architecture , servers, what Google indexes , features and limitations, Google ranking principles and tips, Googleplex

This amazing guide has three simple steps to get a high Google Pagerank:

1. Server Speed: Your website pages must be downloaded nearly at the speed of light. Yes it is, Google gives more visibility to websites that are resident on fast servers.

2. Site Updating: Googlebot has the ability to check out WHEN your pages have been uploaded to the server. Here’s a simple hack - Upload all your pages everyday even if nothing has changed.

3. Lots of light HTML pages: Google adores simple websites with hundreds of pages. If you are building a page that (because of its extensive contents) is going to be larger than 50K , split it in two or three pages.

If you want to know something more about Google file system and architecture, read these PDFs:
The Google File System
The Google (cluster) Architecture

Read Google Ranking - the Definitive Guide by Googlerank: How Google works - overview and features

The Economist reveals some more interesting facts about Google.

When you perform a Google search, you are not actually searching the web, but rather an index of the copy of the web stored on Google’s servers. The index is compiled from all the pages that have been returned by a multitude of spiders that crawl the web, gathering pages, extracting all the links from each page, putting them in a list, sorting the links in the list in order of priority (thus balancing breadth and depth) and then gathering the next page from the list.

When a user types in a query, the search terms are looked up in the index (using a variety of techniques to distribute the work across tens of thousands of computers) and the results are then returned from a separate set of document servers (which provide preview “snippets” of matching pages from Google’s copies of the web), along with advertisements, which are returned from yet another set of servers. All of these bits are assembled, with the help of PageRank, into the page of search results. Google manages to do this cheaply, in less than a second, using computers built from cheap, off-the-shelf components and linked together in a reliable and speedy way using Google’s own clever software. Together, its thousands of machines form an enormous supercomputer, optimised to do one thing—find, sort and extract web-based information—extremely well.