Online search engine leader Google Inc. added an additional 1 billion pages to its Web index Tuesday, increasing its breadth by about one-third as it girds for tougher competition from Yahoo! Inc. and Microsoft Corp.
Google"s search engine now spans 4.28 billion Web pages, up from 3.3 billion pages earlier this week. The Mountain View, Calif.-based company also said it has enlarged its index of Web images to 880 million, up from slightly more than 400 million.
Even with the expansion, Google still isn"t close to capturing the constantly expanding constellation of online content. By some estimates, there are 10 billion pages on the Web.
Nevertheless, the expansion underscores Google"s determination to remain the Internet"s most popular search engine -- a prized position that formidable rivals like Yahoo and Microsoft hope to capture.