Have you wondered how Google is able to detect and stop artificial link building schemes designed to unfairly manipulate search rankings? SpamBrain, one of Google's artificial intelligence systems, allows them to neutralize the impact of manufactured links. SpamBrain makes it so that Google can neutralize unnatural links rather than penalize for them.

It's not perfect, but it's continually learning and improving, making it more and more difficult to prop up rankings with link building.

In this article, I'll share my thoughts and theories about how SpamBrain leverages machine learning to identify unnatural link patterns. I'll explain how Google likely uses this system to discount artificial links rather than penalize sites directly. And also, how SpamBrain reduces the need for Google to rely on links as a quality signal.

Buying and selling links are against Google's spam policies

Google's spam policies say that any link intended to manipulate rankings may be considered link spam.

This week, someone sent an email to Google trying to sell manipulative links. Ooops.

Danny Sullivan, the Google Search Liaison reminds us that buying and selling links is against Google's spam policies.

Can you get competitors penalized by pointing paid links at them?

Some interpreted Danny's words to mean that a site will be penalized if Google catches them building links in an attempt to manipulate rankings. If true, then could we not just buy links and point them at our competitors to get them penalized?

  • "Begins buying links to competitor sites..." AdioKing.eth
  • "Where should I pitch to with a list of my competitors?" Olesia Korobka

To understand this more, let's look at SpamBrain.

What is SpamBrain?

SpamBrain is Google’s sophisticated AI system that is designed to neutralize artificial link building schemes meant to manipulate search rankings.

There’s little written online about how SpamBrain works. Google says SpamBrain can “detect both sites buying links, and sites used for the purpose of passing outgoing links.”

It is a machine learning system.

SpamBrain is a machine learning system

While the exact workings of this system are unknown, I have some theories on how SpamBrain works.

Thoughts on how the SpamBrain system works

The way that machine learning systems tend to work is by looking at example after example of "good" results vs "bad" results. In the case of SpamBrain, Google likely provides it with large datasets of links that were earned organically and naturally versus links that were artificially manufactured with the intent of manipulating PageRank. These categorized links allow SpamBrain to recognize distinguishing patterns.

They can then create a model that can predict if a link is likely a natural mention or unnaturally built for SEO purposes.

Sites that frequently build artificial links develop detectable patterns.

For sites acquiring artificial inbound links, SpamBrain can neutralize those links, preventing an unfair ranking boost.

Sites that frequently sell or publish unnatural links can be detected as well. SpamBrain can neutralize the search ranking abilities of their outbound links.

In either case, the worst that happens is that links that were built for ranking purposes (or in nefarious cases - for attempts at negative SEO against your competitors), are simply not counted for anything. If you built a bunch of unnatural links pointing at your competitor in an attempt to get them penalized, likely what would happen is that Google would likely recognize the pattern of unnatural linking and neutralize them. This would do no harm to your competitor.  

Can a site be demoted by SpamBrain?

I do think there are cases where a site can be algorithmically demoted for widespread link manipulation, but this is rare. In most cases, Google can likely neutralize the links and doesn’t need to penalize a site for having them. If you have a really complicated mixture of links that are SEO made that are difficult to distinguish from links that are naturally earned, and if Google’s algorithms aren’t able to neutralize the SEO made ones, they may decide to give you a manual action or neutralize all of your links.

“If Penguin sees signs of manipulation, it can decide to discount ALL of the links, which can be pretty bad for a site.” - Gary Illyes, Pubcon 2016

In my experience, algorithmic suppression because of link building is not something that is common. Manual actions are becoming less common as well. 

If your traffic is declining lately, it is quite unlikely to be because SpamBrain has penalized your site. However, it may be because some links that previously were helping you have now been detected as artificial and neutralized by SpamBrain. This is especially true for sites with a decline starting December 14, 2022 when Google's link spam update ran. However, this is difficult to diagnose as we were in the midst of a helpful content update as well as a holiday season at that time.

The bottom line: SpamBrain uses machine learning systems (AI) to identify and neutralize attempts to manipulate rankings through unnatural links, rather than penalizing sites directly.

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