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Engines of the future: Into the deep web

作者:常垩    发布时间:2017-05-09 04:00:19    

By Duncan Graham-Rowe Read more: Engines of the future: What’s next in internet search? Search engines see only one in 500 of the accessible pages out there – but a new approach could open up vast new data mines With billions of web pages in their indexes, you might imagine that if something is online, search engines will find it for you. In reality, the vast majority of web pages are effectively invisible to them. Some of this “deep web” contains isolated pages with few, if any, hyperlinks, making them difficult to index. Much is stuff you wouldn’t want to see anyway: web pages detailing old flight reservations, for example, or out-of-date product reviews on Amazon. However, a large proportion are believed to contain openly accessible databases of everything from information on used cars to the prices of airline seats. Even ignoring password-protected and other private sites, the deep web is estimated to be at least 500 times the size of the “surface” web visible to search engines. And by some estimates only 16 per cent of the surface web has been indexed by search engines – that is just 0.03 per cent of the whole (see “Lost in cyberspace”). Juliana Freire at the University of Utah in Salt Lake City thinks that even this figure is over-optimistic. She is developing Deep Peep,

 

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