Google's John Mueller confirmed again that Google won't likely penalize or give your site a manual action if you do not add a nofollow or rel sponsored attribute to your affiliate links. He said this at the 31:58 mark in this past Friday's video.
The question was "Would I be penalized if I don't set the rel sponsored or rel no follow for my affiliate links?" John responded "Probably not."
John did add that is is best practice to do add a nofollow or rel sponsored to the link, as we covered in February 2020, Google prefers we use rel sponsored on affiliate links. John said "So from our point of view, affiliate links fall into that category of something financial attached to the links, so we really strongly recommend to use this setup. But for the most part if it doesn't come across as you selling links, then it's not going to be the case that we would manually penalize a website for having affiliate links and not marking them up." He added "It is a best practice and I strongly recommend doing that, but it's not something where I'd say we will go off and manually take action on these sites."
Here is the embed where John said this:
Why will Google not penalize a site if it does not put a nofollow on those links? Well, Google already treats most affiliate links as nofollowed even if they do not have the nofollow on them. This includes Amazon affiliate links and others. In fact, almost ten years ago, Matt Cutts pretty much said the same thing:
Here is how Glenn Gabe summed it up on Twitter:
More from @johnmu: It's definitely a best practice and John recommends setting up nofollow and/or rel sponsored for affiliate links, but it's not the case that Google would manually take action on those affiliate sites if the links aren't marked up: https://t.co/y3zhvVIJbX pic.twitter.com/HSyyZWHBIc
— Glenn Gabe (@glenngabe) December 14, 2021
Forum discussion at Twitter.