IS there no stopping Google? Last month the company鈥檚 share price topped $400 per share 鈥� that鈥檚 nearly five times their worth when the company floated on the US stock exchange 15 months ago. Its market value is now $118 billion, higher even than Coca-Cola. Google is now a household name. But the role of Backrub, the software program that is key to the search engine鈥檚 astonishing success, is less well known.
It all started in 1995. In those days, indexing the web was a lengthy task. The early search engines were notoriously inaccurate because they had no way to rank the results of any search. A search for the computer company Apple, for example, was just as likely to throw up sites about Granny Smiths as the company鈥檚 home page.
How could a search engine work out how to order these results? It turns out that the web itself holds the answer. Working out which websites a particular page points towards is easy 鈥� you just follow the links, mapping out the web as you go. But the reverse process of working out which pages point to the one you are on is hard. In 1995 Larry Page, a young computer science graduate at Stanford University in California, became fascinated by these backlinks and wrote a program called Backrub to hunt for them.
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The crucial thing that Page realised was that backlinks could be used to rank the results of a search because they are a kind of stamp of approval. The more sites that point to a page, the more popular it must be. But certain backlinks are better than others: it is more valuable to have a link from CNN.com, for example, than from Aunt Nellie鈥檚 marmalade emporium. So Backrub ranked websites not only by how many sites pointed to it, but also by how important those sites were.
鈥淚t is hard to work out which pages point to the one you are on鈥�
It was a revolution in the making. Page and his friend at Stanford, Sergey Brin, who was also working on the project, let Backrub loose in March 1996 and soon after changed its name to Google. The rest, as they say, is history. Google鈥檚 results were so clearly superior to the competitors of the day 鈥� Yahoo was still employing humans to rank websites by hand 鈥� that its popularity rose spectacularly.
What of the future for search engines? Yahoo is testing a new type of search engine called Y!Q which attempts to give more relevant results by assessing the context of your search. Cyc is an artificial intelligence program soon to be released onto the web that its makers say will understand questions and answer them accordingly. Then there are sites such as , and which all claim to have a new take on searching. Meanwhile, Google is not sitting on its hands.
There is no shortage of pretenders to the search engine throne. But for the moment, Google 鈥� aka Backrub 鈥� is still king.
