Monday Briefing: ChatGPT Is Now Half the Market

Good morning, it's James here. For two weeks I’ve tracked ChatGPT's ad business in this very weekly post. New data says the audience has been spreading to other assistants the whole time.

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The Lead: ChatGPT Is Now Half the Market

What happened. Comscore panel data shows ChatGPT's share of AI prompt volume fell from 70% to 50% between January and June. Gemini nearly doubled, from 17% to 30%, and Claude climbed from 2% to 11% (Digiday). The panel covers 500,000 to 1 million opt-in users. Total usage kept growing under the share shift. In June, 35% of desktop users and 29% of mobile users visited an AI assistant, up from 25% and 12% in January 2025. Google desktop searches with an AI Overview rose from 25.8% to 39.4% in a year.

Why CMOs should care. Most AI visibility work I see starts and ends with ChatGPT. Someone on the team types the category prompts into it, screenshots the answers and sends them up the chain. That process now checks half the market, and the half that is losing share. Google is building on the other half. Its Demand Gen update last Thursday added Business Agent for YouTube Ads, where "viewers can engage with conversational AI alongside video ads with product feeds, getting immediate answers about products or brands without leaving their viewing context" (Google). Advertisers sign up through a form.

The take. Last week I asked who owns what your brand agent says. Add a second question. Where does it say it? Run the same 20 prompts through ChatGPT, Gemini, Claude and Google's AI Overviews every month and track the answers side by side. If your agency's AEO report covers one assistant, ask for all four before you approve the next invoice. On Google's agent, it runs on video ads with product feeds. I would assume the feed is most of what it knows about you. In most companies the feed is maintained three levels below the brand team. Find out who that is this week.

Brand Spotlight: Beats Launched Headphones With No Paid Media

Before Beats announced the Beats 360, athletes including Lamine Yamal wore unreleased pairs in public. None of them had to under their contracts, and no paid media supported the pre-launch run (The Drum). CMO Chris Thorne said fans went looking for sightings. "It just became this fun, almost Easter egg-like thing that consumers were looking for."

His reasoning connects to the Lead. AI search now shapes what shoppers see when they research a product, and Thorne said, "It's less important nowadays what you say about yourself and that's the way it should be." Assistants summarize what other people say about you. Beats built a launch that produced more of that before it paid for reach. Most of us cannot put headphones on a Barcelona winger. We can look at next quarter's launch plan and count how many dollars go to material an assistant would actually cite.

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What I'm Watching: Sephora Is Sending Its Shoppers to TikTok

Sephora released a 12-piece POV Beauty holiday set, "$327 value for $265," as a TikTok Shop exclusive. It launched on a livestream hosted by POV co-founder Mikayla Nogueira (Digiday). The product page on Sephora's own site sends shoppers to TikTok. At publication Sephora had sold close to 2,300 products there.

The sales figure is small. The platform behind it is large. TikTok Shop is now the No. 4 health and beauty retailer in the U.S., with more than $4.4 billion in category sales since its 2023 launch. Blaine Nielsen of Rithum described the retailer's position. "They would prefer that the world comes to their own domain, and they can control that experience. But the world doesn't really work that way." His open question is whether these buyers come back or stop at one trial purchase. Watch for a second Sephora exclusive in Q1. If one comes, expect your retail partners to ask what your brand has planned for TikTok Shop.

The Reading List

• Marketers on AI's "good enough" standard (Digiday) One brand marketer says, "I've seen lots of creative executions from our agencies, and our logo isn't right." Send it to whoever signs off on agency work.

• Channel 4's Katie Jackson on talkability (The Drum) Channel 4's data says that among 16- to 34-year-olds, shows people talk about are now the second biggest driver of streaming platform consideration.

• The case for and against retail media as a brand channel (Digiday) The best line describes retail media audiences as "modeled off of a receipt."

• Netflix rolls out pause ads (Advanced Television) Programmatic pause ads arrive in October, with new income and household composition targeting.

• How Jeep is charting a new course for its marketing (Marketing Dive) "This Is Jeep Country" goes all in on Americana, starting from the line "America was the Jeep brand's first customer."

One More Thing

These share numbers will move again before year end. If you check four assistants every month, you will see the next shift in your own data before you read about it here.

See you next Monday. Until then, make it count.

—James