The "Who indexes more billion pages" war started in August, when the team behind Yahoo Search posted on the official blog the information that it searches through 20 billion documents. To be more exact, Yahoo Search claims to index 19.2 billion web pages and 1.6 billion images, not counting the 50 million audio and video files.
At
the time, Google, the only search engine displaying the number of indexed pages, had a little over 8 billion documents.
The debated started almost instantaneously and everyone was expecting to say that they index more pages than Yahoo. But Google's response was that it doesn't matter the size, the relevance being more important, the "do no evil company" insinuating that the 20 billion pages don't mean anything if the relevance is low.
To prove that the number doesn't matter, Google, which turns 7 today, has decided to remove the counter of indexed pages. On the official blog, Anna Patterson explained Google's new concept on index size and the computation method for it. You can find out more
here.