en.wikipedia.org/wiki/PageRank

The statement is no longer correct because the relevant PageRank patent has expired.

Evidence:

• Google Patents lists US6285999B1, “Method for node ranking in a linked database” as “Expired - Lifetime” and shows an anticipated expiration date of January 9, 2018.
• The USPTO explains that after a patent has expired, anyone may make, use, offer for sale, or sell the invention without permission.

So while Google may previously have held an exclusive license from Stanford, that exclusivity does not continue after expiration. Once the patent expired, the patented invention entered the public domain for patent-law purposes, and Google no longer had exclusive rights to exclude others from using it.

This claim is too broad.

It is true that the original Stanford PageRank patent — US6285999B1, “Method for node ranking in a linked database” — is expired. However, that does not mean that all patents associated with PageRank had expired by September 24, 2019.

A direct counterexample is US9495452B2, “User-sensitive PageRank.” Google Patents lists that patent as active and shows it expires on August 6, 2027. Because that patent explicitly concerns PageRank and was still active long after September 24, 2019, the article’s blanket statement that all PageRank-associated patents had expired by that date is incorrect.

So the accurate version would be closer to: the original PageRank patent expired, but not every patent related to PageRank had expired by September 24, 2019.

This sentence is no longer accurate.

First, Google stopped offering public PageRank scores years ago. Coverage of Google’s 2016 change notes that Google removed Toolbar PageRank, meaning webmasters and the public no longer had access to a visible PageRank number.

Second, Google’s own current Search documentation says its ranking systems are designed to work at the page level, using many signals and systems to rank individual pages. Google also says that while site-wide signals exist, they do not mean all content from a site will rank the same way. That contradicts the idea that Google offers a single homepage PageRank as its best indicator of overall "website authority."

So the statement is outdated on two levels: Google no longer publicly offers PageRank for a homepage, and Google’s current ranking documentation does not describe a single homepage metric as its public measure of website authority.