Recent research sheds light on the contrasting nature of results generated by traditional search engines versus their AI-powered counterparts. The findings indicate that AI-powered search engines rely on “less popular” sources than conventional search algorithms when compiling information for users. This divergence raises questions about the quality, reliability, and diversity of information presented by these emerging technologies.
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Official guidance: W3C – official guidance for AI-powered search engines rely on “less popular” sources
Background Context
A study conducted by researchers at Ruhr University in Bochum, Germany, and the Max Planck Institute for Software Systems, meticulously compared the search results from Google’s traditional link-based search with its AI Overviews, Gemini-2.5-Flash, GPT-4o’s web search mode, and GPT-4o with Search Tool. The team utilized diverse query sources, including questions submitted to ChatGPT in the WildChat dataset, general political topics from AllSides, and popular Amazon product searches. The central finding reveals that AI-powered search engines rely on “less popular” sources than traditional search engines.
The research methodology involved analyzing the domain popularity of websites cited by each search engine using Tranco, a domain tracker. The results indicated that sources cited by generative search tools were significantly less popular than those appearing in the top 10 of a traditional Google search. In fact, these AI-driven sources were more likely to fall outside the top 1,000 or even the top 1,000,000 domains tracked by Tranco. This trend was particularly pronounced with Google Gemini search, where the median source cited often ranked outside Tranco’s top 1,000 domains. This demonstrates how AI-powered search engines rely on “less popular” sources when compared to the top search results from Google.
Source Diversity and Content Characteristics

Further analysis revealed that a substantial portion of sources cited by AI Overviews, specifically 53%, did not appear within the top 10 Google search results for the same query. Moreover, 40% of these sources were not even present within the top 100 Google links. This highlights a significant departure from the conventional ranking system employed by traditional search engines. While this doesn’t inherently imply inferiority, it underscores the different approaches to information retrieval and presentation. It’s becoming increasingly apparent that AI-powered search engines rely on “less popular” sources to formulate their responses.
The research also explored the types of sources favored by AI-powered search engines. GPT-based searches, for example, exhibited a preference for citing corporate entities and encyclopedias, while largely avoiding social media websites. An LLM-based analysis tool indicated that AI-powered search results covered a similar range of identifiable “concepts” as the top 10 traditional links, suggesting comparable levels of detail and novelty. However, the study also noted that generative engines tend to compress information, potentially omitting secondary or ambiguous aspects that traditional search retains. This compression can be a drawback for ambiguous search terms, where organic search results may provide more comprehensive coverage. The shift in source preference is a key indicator that AI-powered search engines rely on “less popular” sources to create their summaries.
Implications for Timeliness and Accuracy

While AI-powered search engines benefit from integrating pre-trained “internal knowledge” with information from cited websites, this approach can present limitations, especially when searching for timely information. GPT-4o with Search Tool, for instance, sometimes struggled to provide up-to-date information for trending queries, often responding with requests for more information instead of actively searching the web. This reliance on pre-trained data can hinder its ability to deliver current and accurate results in certain situations. This limitation underscores the fact that AI-powered search engines rely on “less popular” sources, and their internal knowledge may not always be sufficient.
The study’s findings have significant implications for how we perceive and utilize AI-powered search engines. The tendency to cite less popular sources raises concerns about potential biases and the overall credibility of the information presented. While the researchers refrained from definitively labeling AI-based search engines as “better” or “worse” than traditional search, they emphasized the need for future research to develop “new evaluation methods that jointly consider source diversity, conceptual coverage, and synthesis behavior in generative search systems.” This is especially important given how AI-powered search engines rely on “less popular” sources.
Future Research Directions
The research underscores the evolving landscape of search technology and the need for ongoing evaluation and refinement of AI-powered search engines. Future investigations should focus on understanding the long-term effects of these changes on information consumption, source credibility, and the overall quality of online content. Further exploration into why AI-powered search engines rely on “less popular” sources is warranted.
In conclusion, the study provides valuable insights into the contrasting approaches of traditional and AI-powered search engines. The finding that AI-powered search engines rely on “less popular” sources highlights the need for critical evaluation and further research to ensure the accuracy, diversity, and reliability of information presented by these increasingly prevalent technologies. As AI continues to reshape the search landscape, it is crucial to understand its strengths, weaknesses, and potential biases to leverage its capabilities effectively while mitigating its risks.
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