Context
An ACM Web Conference 2026 short paper studies how synthetic and adversarial web content alters retrieval and RAG source exposure in controlled experiments.
What changed
In an SEO-style synthetic-content scenario, 67% synthetic source-pool contamination produced more than 80% exposure contamination, even while answer accuracy could remain stable. Under adversarial contamination, BM25 exposed about 19% harmful content; tested LLM-based rankers suppressed more.
Why it matters
Source diversity, synthetic-content exposure, and retrieval integrity can degrade without immediate drops in answer accuracy, complicating the measurement of trustworthy AI discovery.
Visibility OS interpretation
Visibility OS interpretation: evaluate source-pool composition and exposure separately from final answer correctness. These are controlled retrieval findings, not measurements of any named commercial AI search platform.
What remains uncertain
How do results transfer to live web-scale indexes, evolving AI-generated content and production rerankers? What mitigation improves source diversity without suppressing useful original content?