AI Search Engines Assign Roles to Sources

Research from BrightEdge comparing citations in ChatGPT and Google AI Overviews indicates that AI search systems are doing more than simply pulling information from the web. Instead, they appear to assign different “roles” to the same platforms, treating sites such as Reddit and LinkedIn as authoritative references in some cases, while viewing them as social commentary in others.

For marketers, SEOs and publishers, the findings suggest that visibility in AI search is no longer just about being cited. It is increasingly about understanding how each AI system interprets and uses a given source within its responses.

AI Systems Treat the Same Sources Differently

A key takeaway from the research is that identical sources can be handled very differently depending on which AI engine generates the answer.

Reddit’s Changing Citation Role

Reddit appears alongside established reference and medical sites such as Mayo Clinic, Healthline, Cleveland Clinic and Britannica in around 36% of ChatGPT citations. In contrast, within Google AI Overviews, those same authoritative sources appear with Reddit far less frequently, at roughly 6%.

Instead, Google’s AI Overviews tend to group Reddit with other social platforms. For example, YouTube is seen alongside Reddit in around 36% of citations, while Facebook, TikTok and Instagram also frequently appear in similar contexts.

BrightEdge describes this as a “six-fold authority shift”, where the same Reddit content can be positioned differently depending on the AI system interpreting it.

This distinction matters for marketers, as the surrounding sources influence how the AI “reads” a citation. A mention is not neutral; it carries context.

When Reddit appears alongside medical and editorial sources, it is treated more like a trusted reference. When it appears next to social platforms, it is interpreted more as public opinion or user sentiment.

In effect, AI systems are making editorial-style decisions about how sources should be used.

Different AI Systems Use Sources for Different Tasks

The research also shows that ChatGPT and Google AI Overviews rely on Reddit and LinkedIn in different ways depending on the type of query.

For “how-to” and explanatory searches, Reddit is cited roughly twice as often in ChatGPT compared with Google AI Overviews. LinkedIn also appears in both systems, but more frequently in ChatGPT responses (33%) than in AI Overviews (22%).

For “why” or explanation-based queries, ChatGPT leans more heavily on Reddit, while Google AI Overviews tends to surface different types of social context depending on the prompt.

Comparison-style queries also show divergence. Around 10% of Google AI Overviews’ social citations relate to comparison searches such as “X vs Y”, compared with only around 1% in ChatGPT.

This suggests that ChatGPT is more likely to directly construct comparisons, while Google’s AI Overviews draw more from existing public discussions where comparisons are already being debated.

Verification-based queries, which make up roughly 14% to 24% of prompts across both systems, further highlight differences. LinkedIn is more commonly used for professional validation, whereas Reddit is more often used for consumer reassurance and lived experience.

AI Systems Appear to Assign “Functions” to Platforms

One of the most notable insights is that AI engines do not just select sources; they appear to assign them specific functions.

LinkedIn is more commonly used in professional, career and B2B contexts. Reddit, on the other hand, is more frequently used for consumer-facing topics such as health, finance and product research.

This suggests that platforms are being categorised by the type of information they are perceived to provide, rather than being treated equally across all queries.

Implications for AI Search Strategy

The findings indicate that AI search cannot be approached as a single, uniform channel.

A Reddit discussion, for example, may be treated as an authority signal in ChatGPT but interpreted as general user sentiment in Google AI Overviews. Similarly, LinkedIn may carry more weight for professional queries but less relevance for consumer-focused searches.

This means that visibility is no longer just about being mentioned, but about the context and function of that mention within AI-generated answers.

The study suggests that AI systems are increasingly making editorial decisions about sources, assigning them roles based on the type of question being asked.

What the Research Reveals About AI Search Behaviour

The broader conclusion is not simply that ChatGPT and Google AI Overviews cite Reddit and LinkedIn differently, but that both appear to categorise sources according to purpose.

Reddit may act as authority in one context and social proof in another. LinkedIn may serve as a professional verification source across B2B queries. These roles shift depending on the intent behind the question.

Unlike traditional search engines, which primarily rank pages based on relevance, AI systems appear to interpret and classify sources before using them in responses.

This shift suggests that understanding how AI systems “position” different platforms may become just as important as achieving citations themselves.