A few years ago, Google kind of got caught violating its own webmaster guidelines. Specifically, a third party was doing some marketing for the company to promote Chrome, and they reportedly paid bloggers with gift certificates for sponsored posts. The links were not nofollowed, which is what you're supposed to do according to Google.
Google said at the time, "Google never agreed to anything more than online ads. We have consistently avoided paid sponsorships, including paying bloggers to promote our products, because these kind of promotions are not transparent or in the best interests of users. We're now looking at what changes we need to make to ensure that this never happens again."
Once outed, Google did play by the rules and penalize the Chrome site. They may want to take another look at those changes they made to ensure it never happened again though, because it sounds like it happened again.
Barry Schwartz at Search Engine Roundtable reports:
Tadeusz Szewczyk posted on Twitter that Google paid $350,000 or so to buy an image link for Google Chrome on the Let's Encrypt sponsors page. Google is a big backer of encryption and there is no doubt they are supporting this cause. But as you can see, platinum sponsorship is $350,000.
Google has yet to address this to our knowledge. Will it penalize Chrome again?
Update: Google has now addressed it in a Webmaster Central hangout video (52 minutes in):
Evidently, Google was not counting the link anyway and it has been nofollowed. According to Google's John Mueller, the link would't have changed the ranking of the Chrome home page anyway.
Read Barry's recap here.
Image via Google