I have repeatedly made the claim that AI chatbot traffic converts better than search engine traffic.
My thinking was that ChatGPT or Perplexity users go through evaluation and exploration cycles (remember the Messy Middle) faster and are closer to a purchase intent when they click on an outgoing link.*
But I couldn’t prove it at scale. Until now.
*Of course, there must be an impact of seeing brands mentioned in AI chatbots even without a link, but that’s not the focus of this study.
To prove this mental model right or wrong, Similarweb provided me with a large dataset of over 7 million referral sessions from ChatGPT, Copilot, Gemini, and Perplexity with Google Search across September, October, and November in the U.S.
The data focuses on transactional referral traffic. Due to its industry size, I notice a heavy bias toward ecommerce, but the data also covers conversions like software sign-ups.
Thanks to the Similarweb team, especially Lewis and Adelle, for supporting me with the data and your time.
Before jumping in, I want to point out a big caveat: AI chatbot referral traffic is still tiny compared to Google.
In How significant is AI chatbot traffic in B2B?, I found AI chatbot traffic to make up less than a percent of organic traffic today.
It’s growing at a rapid rate and could catch up over the next years, but reality is that it’s still small.
AI chatbot traffic (in SaaS) – Image Credit: Kevin Indig
Same ‘Ol, Same ‘Ol
I want to start with a look at the top 10 landing pages because it’s representative of how to think about the rest of the data in this study.
About 80% of (transactional) traffic to top the top 10 landing pages goes to ecommerce sites.
And, it’s mostly to the same players you already know from (Google) Search because AI chatbot answers use search results to ground (think: weight) their answers.
Top 10 landing pages by traffic from referrer (Image Credit: Kevin Indig)
Amazon, eBay, and Walmart dominate in Google Search just as much as in AI chatbots.
Microsoft appears surprisingly often in the top 10 landing pages, apparently because searchers are looking for software like Copilot or Teams.
Thinking one step further, if search results determine who’s visible in LLMs, the sites that dominate right now will also dominate the AI world.
I’m skeptical that this is how it will actually play out because users ask longer queries and have a conversational experience in AI chatbots, which should allow LLMs to develop their own “ranking factors.” What we’re seeing is the very first iteration.
AI Chatbot Traffic Is More Engaged
The big question I’m trying to answer is whether AI chatbot referrals convert better than search traffic.
I looked at two metrics to compare the traffic quality of each referral source: session duration and the number of page views per session.
High session duration in combination with a high number of (non-bounced) page views means users evaluate a product for longer and are more likely to buy when looking at transactional traffic.
Avg session duration by referrer (Image Credit: Kevin Indig)
The trend is crystal clear: AI chatbot referrals stay more than a minute longer than Google traffic.
The front runner is Copilot, with an average of 11.6 minutes per session. On average, AI chatbot traffic stays for 10.4 minutes, compared to Google’s 8.1 minutes.
Avg session duration and number of non-bounced pageviews by referrer (Image Credit: Kevin Indig)
To put session duration into perspective, I wanted to see if users who stay longer also visit more pages on a site. The answer is “yes.”
AI chatbot referrals visit 12.4 pages on average, compared to Google’s 11.8.
Again, more pageviews within the same session correlate with a higher chance of conversion when looking at transactional traffic, so this means AI chatbot traffic has a higher quality.
The average might not seem big, but luckily, Similarweb sent me data by month as well, so I was able to look at the trend over time.
I found that the number of non-bounced page views from Copilot and Perplexity grew faster than from Google between September and October: 15% and 22%, compared to Google’s 5%.
Gemini’s non-bounced page views shrunk by -11% over the same time and ChatGPT by -5%, which is reasonable given its rapid traffic growth.
Session duration vs. visits on chatgpt.com (Image Credit: Kevin Indig)
In general, it’s impressive that ChatGPT’s session duration grows while traffic is exploding. It means that the models are getting better at answering questions while more people are using them.
Google’s session duration and traffic are flat in comparison, but with the context that Google is a matured channel and magnitudes larger than ChatGPT.
Total traffic to Copilot vs. Perplexity (Image Credit: Kevin Indig)
To my surprise, Microsoft Copilot traffic shows better engagement than Perplexity, which has higher adoption and launched a specific ecommerce feature (Shop with Pro).
Copilot is not as far away from Perplexity as you might think (14 vs. 21 million visits in December 2024), and both saw big traffic gains in October 2024.
I explain this trend with Microsoft’s roll-out of Copilot on all of its devices and software products.
AI Chatbots Send More And Better Traffic To Homepages Than Google
To understand where AI chatbot referrals land and compare it to Google, I looked at folder depth as defined by the number of slashes in a URL after the domain name.
Higher folder depth = more folders in the URL = “deeper” in the site architecture.
A search for a transactional keyword on Copilot (Image Credit: Kevin Indig)
For example, a search for “best cheap fridge magnets” in Copilot leads you to www.amazon.com/Best-Sellers-Refrigerator-Magnets/zgbs/kitchen/3737161?form=MG0AV3, which has a folder depth of 4.
Notice how Copilot references only Amazon results, even though Bing ranks Amazon No. 3 and No. 4 for the query.
The first (Printrunner) and second results (Uprinting) don’t allow you to buy fridge magnets but to design them. It seems that Copilot understands that.
My theory was that a higher folder depth means more traffic goes to specific products (ecommerce) and landing pages (B2B).