In 1998 Google had 26 million indexed pages. It went further north to one billion in 2000. In 2005, however, Yahoo announced that it had indexed 20 billion URLs prompting Google to rebuke the claim. So let's see how Yahoo will react to this statement from Google:
"Over the last eight years, we've seen a lot of big numbers about how much content is really out there. Recently, even our search engineers stopped in awe about just how big the web is these days– when our systems that process links on the web to find new content hit a milestone: 1 trillion (as in 1,000,000,000,000) unique URLs on the web at once!"