Google's Algorithm now includes more than 200 components to its "secret sauce":

Mr. Singhal has developed a far more elaborate system for ranking pages, which involves more than 200 types of information, or what Google calls “signals.” PageRank is but one signal. Some signals are on Web pages — like words, links, images and so on. Some are drawn from the history of how pages have changed over time. Some signals are data patterns uncovered in the trillions of searches that Google has handled over the years.

“The data we have is pushing the state of the art,” Mr. Singhal says. “We see all the links going to a page, how the content is changing on the page over time.”

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