Rand Fishkin writing at the SparkToro Blog with a bombshell leak of policies from Google on how its search algorithm works:

On Sunday, May 5th, I received an email from a person claiming to have access to a massive leak of API documentation from inside Google’s Search division. The email further claimed that these leaked documents were confirmed as authentic by ex-Google employees, and that those ex-employees and others had shared additional, private information about Google’s search operations.

Many of their claims directly contradict public statements made by Googlers over the years, in particular the company’s repeated denial that click-centric user signals are employed, denial that subdomains are considered separately in rankings, denials of a sandbox for newer websites, denials that a domain’s age is collected or considered, and more.

These documents are really sending the SEO industry into a tailspin this week. This is a fascinating look into one of the most closely guarded secrets in tech.

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Mike King also received the documents and has a great breakdown on iPullRank:

I have reviewed the API reference docs and contextualized them with some other previous Google leaks and the DOJ antitrust testimony. […]

You’d be tempted to broadly call these “ranking factors,” but that would be imprecise. Many, even most, of them are ranking factors, but many are not. What I’ll do here is contextualize some of the most interesting ranking systems and features (at least, those I was able to find in the first few hours of reviewing this massive leak) based on my extensive research and things that Google has told/lied to us about over the years.

“Lied” is harsh, but it’s the only accurate word to use here. While I don’t necessarily fault Google’s public representatives for protecting their proprietary information, I do take issue with their efforts to actively discredit people in the marketing, tech, and journalism worlds who have presented reproducible discoveries.

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At first, there was silence from Google on this leak. Yesterday, The Verge received email confirmation with a statement:

“We would caution against making inaccurate assumptions about Search based on out-of-context, outdated, or incomplete information,” Google spokesperson Davis Thompson told The Verge in an email. “We’ve shared extensive information about how Search works and the types of factors that our systems weigh, while also working to protect the integrity of our results from manipulation.”