Google has explained the way its search results are ranked following increasing scrutiny from regulators concerning its dominant market position.
Singhal, a 20-year veteran of the search industry, admitted that Google's algorithms are not perfect, but insisted that they do work.
"After nearly two decades, I've lost count of how many times I've been asked why Google chooses to generate its search results algorithmically. Here's how we see it: the web is built by people," he wrote.
"You are the ones creating pages and linking to pages. We are utilising all this human contribution through our algorithms to order and rank our results. We think that's a much better solution than a hand-arranged one."
As an example of how fair Singhal believes the system to be, he used a query for 'search engines' on Google. The top four results are AltaVista, Dogpile, Bing and Ask.com.
Singhal acknowledged that other search engines take a different approach, but argued that these too are imperfect.
"Other search engines approach this differently, selecting some results one at a time, manually curating what you see on the page," he said.
"We believe that an approach which relies heavily on an individual's tastes and preferences just doesn't produce the quality and relevant ranking that our algorithms do.
"And given the hundreds of millions of queries we have to handle every day, it wouldn't be feasible to handle each by hand anyway."
Google tinkers with the algorithms every day, according to Singhal, and uses many different 'signals' to create its search results.
"There's a ton that goes into building a state-of-the-art ranking system like ours. Our algorithms use hundreds of different signals to pick the top results for any given query," he said.
"Signals are indicators of relevance, and they include items as simple as the words on a web page or more complex calculations such as the authoritativeness of other sites linking to any given page.
"Those signals and our algorithms are in constant flux, and are constantly being improved. On average, we make one or two changes to them every day."
Singhal reiterated that search is not perfect, but said that Google continues to work at the technology.
"Ultimately, search is nowhere near a solved problem. Although I've been at this for almost two decades now, I'd still guess that search isn't quite out of its infancy yet," he explained.
"The science is probably just about at the point where we're crawling. Soon we'll walk. I hope that, in my lifetime, I'll see search enter its adolescence. "
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