Brilliant Thinking

Yahoo! 20.8 billion vs Google 8.2 billion

But size isn’t everything The effectiveness of a search engine is not dictated solely by the size of its index, and most experts agree that Google still churns out the most accurate results, helping it to maintain a lead in terms of user figures globally.

More at: http://www.theregister.co.uk/2005/08/09/yahoo_biggest/