Google Blog

Google Blog: "The documents in Google's index are in dozens of file types from HTML to PDF, including PowerPoint, Flash, PostScript and JavaScript. Together these pages represent a good chunk of the world's information, but hardly all of it. That's why we keep building more advanced systems for crawling the web and creating more sophisticated indices to sort what we find. So 8 billion pages is a milestone worth noting, but it's not the end of the road. The real test is how well we do in finding what you want from within those pages. We'll keep improving that too. "