December 2022 link spam update (SpamBrain)

What changed

Google announced that SpamBrain, its AI-based spam prevention system, had been extended to detect sites buying links and sites used for passing outgoing links. The update ran from 14 December 2022 to 12 January 2023 in all languages. Google said affected links would be neutralised rather than counted, so sites relying on them could see ranking drops, and pointed to its link spam policy documentation.

Timing

Rollout began 14 December 2022. Google declared it complete on 12 January 2023, 29 days later. Rankings typically remain unstable for the whole rollout window, so measurements taken inside it are not a reliable read on the outcome.

What it affected