Google, the most widely used search engine among English speakers worldwide, had reason to celebrate yesterday as its index of internet items passed the six billion mark.
Last August, Google's index had about 4.5 billion items.
"This represents steady improvement as we keep on adding pages. We want to index all the worthwhile pages out there," said Peter Norvig, director of search quality at Google.
Along with growing the index, Google refines its ranking algorithms continually to serve up query results that are as relevant as possible to the user's search.
"There's no doubt that Google is where it is because of the quality and relevance of its search results," said Graham Mudd, a comScore Networks analyst. "Continuing to increase the number and types of items a search engine can be used for can only help in this regard."
Google said the six billion items include about 4.28 billion web pages, 880 million images and 845 million Usenet messages.
A growing category is book-related information pages, including first chapters, reviews and bibliographic information. Google retrieves book-related items through its Google Print service, which is in test mode.
Juan Carlos Perez writes for IDG News Service