Added: July 16, 2019 A Google Search Engineer on a thread at Hacker News told the world that Google stopped using the Stanford Version of PageRank back in 2006, which Barry Schwartz reported upon at Search Engine Roundtable in the post Former Google Engineer: Google Hasn’t Used PageRank Since 2006 That search engineer was Jonathan Tang, who has been an inventor on at least one Google Patent in the past. Tang stated in a longer post the following:
The comments here that PageRank is Google’s secret sauce also aren’t really true – Google hasn’t used PageRank since 2006. The ones about the search & clickthrough data being important are closer, but I suspect that if you made those public you still wouldn’t have an effective Google competitor.
He told us this about the change away from that version of PageRank: