Google faces a challenge from a Silicon Valley start-up that claims to have launched the internet's biggest search engine. Cuil, pronounced "cool", reckons its search index is three times larger than Google's.
Cuil, which is the Gaelic word for knowledge says that it has indexed 120 billion web pages, ranking them by content rather than popularity.
It said that Google does not index them all because they either point to similar content or would diminish the quality of its search results in some other way. The posting did not quantify the size of Google's index.
It said: "We've known it for a long time: the web is big. The first Google index in 1998 already had 26 million pages, and by 2000 the Google index reached the one billion mark.
"Over the past eight years, we have 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: 1,000,000,000,000 unique URLs on the web."
Cuil, in a description on its site, says: "Rather than rely on superficial popularity metrics, Cuil searches for and ranks pages based on their content and relevance." It features a magazine-style layout rather than a single vertical stack.