Google uses an AI system called SpamBrain to automatically detect and remove spam, manipulative, and low-quality content from Google Search results. The system was updated most recently in August 2025, targeting content-level spam including AI-generated pages with no added value, keyword stuffing, and scraped content.

SpamBrain was launched in 2018 and has been continuously retrained. Google's official documentation describes it as an 'AI-based spam-prevention system' that is periodically improved to catch new types of abuse. The August 2025 Spam Update (the first of 2025, rolling out August 26 to September 22) used SpamBrain to target content-level spam including mass-produced AI-generated text without human value, keyword stuffing, scraped content, and thin affiliate pages. Earlier updates in 2024 enforced 'scaled content abuse,' 'site reputation abuse,' and 'expired domain abuse' policies. Google states SpamBrain operates continuously and is supplemented by periodic algorithm updates.