Buyers Said the Agent Ads Would Get Blocked. Four Days Later They Were.

On August 7, Digiday asked a group of media buyers what they made of the new ad format aimed at AI agents. Stephan Kopp, managing director at Mediaplus Performance, gave the shortest answer.

“You can try it to influence LLMs with the ad content, but it will not happen.”

Four days later Perplexity blocked the format outright.

The ads in question sit inside markdown pages, the stripped-down plain-text copies of a webpage that AI systems read instead of the designed version a person sees. We covered the launch on July 31, when Time turned its markdown pages into inventory with the ad tech company Mobian and sold the first slots to Ally Bank and the Project Management Institute. Perplexity has now blocked all markdown advertising on Time.com from influencing either its agents or its ordinary search results.

Jesse Dwyer, Perplexity’s chief communications officer, told Digiday that the company works “continuously” to protect users from deceptive practices, and warned that publishers running “deceptive advertising like markdown ads” risk a reputational downgrade in Perplexity’s index, including a hit to their trust score.

The word doing all the work is “deceptive”

Perplexity did not answer Digiday’s questions about how it defines the term, or how it is blocking the ads.

That matters, because the format’s operator makes the opposite claim in public. Mobian’s own site states that “Every agent ad is labeled as sponsored. The disclosure is the first line of the ad,” that “Every fact carries a source citation,” and that “Every ad is attributed to the brand that paid for it.”

Both statements can’t be describing the same product accurately. Either the disclosure exists and Perplexity is objecting to something other than concealment, or it doesn’t and Mobian’s marketing is wrong. Nobody outside the two companies can currently check, which is itself the story: an ad format was removed from a distribution channel on a judgment nobody has to explain.

Jonah Goodhart, Mobian’s co-founder and CEO, argued the case for the format:

“I think over time the models will want factual information available about the brands that matter to their consumers, so it is a bit perplexing why [Perplexity] would block that content.”

Time did not respond to Digiday’s requests for comment.

The buyers were not surprised

Go back to the August 7 piece and the skepticism was already specific. Danny Weisman, co-founder of Obsessed Media, was not writing it off entirely, but he was clear about where it belonged in a plan:

“It doesn’t strike me as something I’m gonna pursue today.”

“It feels like something that should be added value from these publishers versus like a main campaign.”

Rita Steinberg, VP of media at FUSE Create, drew the line the most usefully: “You can influence AI visibility,” she said. “I just don’t think you can reliably buy it yet.”

She was right within the week, and the reason is structural. The value of a markdown ad depends entirely on whether the AI system reading the page chooses to honor it. It’s a request, made to a company with its own commercial interest in what its answers say, and no obligation to accept.

This is the part that generalizes past Time

Mobian names FOX, Hearst, and The Globe and Mail as publisher partners alongside Time. So the format has distribution, and the block is one engine, not the market. Google, OpenAI, and Anthropic have said nothing about how they’ll treat sponsored blocks in markdown, and their answers will decide whether this is an ad category or an experiment that ran for six weeks.

What Perplexity has established is the shape of the risk. In conventional media buying, the publisher controls the page and the advertiser buys space on it. Here the publisher controls the page, the advertiser buys space on it, and a third party decides at read time whether any of that happened. Perplexity added a second consequence on top: a publisher who sells this inventory may see its whole domain’s trust score marked down, which puts a publisher’s editorial reach at risk to fund an experimental ad product.

That’s an unusually bad trade for a publisher and it’s a worse one for the brand, because the advertiser bears the downside without holding any of the controls.

Test the format if a publisher offers it as added value, exactly as Weisman framed it. Do not fund it from a line that has to deliver, and before signing anything, ask which engines have confirmed they will read it. Right now the honest answer for at least one of them is on the record, and it’s no.

Related coverage: Time built a version of its site for bots, publishers rebuilding the web for AI agents, and OpenAI’s agent ads that replace the landing page.