Ali Miller thinks about Instacart's advertising evolution like a three-act play. 

Act 1 was fundamentals. Act 2 was expanding formats and objectives. Act 3, the one Instacart is in now, is about becoming infrastructure for an entire ecosystem.

Miller was promoted to general manager of advertising at Instacart in July last year, but she's been architecting this trajectory for over four years. Before Instacart, she spent more than a decade at Google, leading the full-stack redesign of Google Ads (then AdWords) before moving to YouTube, where she directed product for the ads advertiser experience. At YouTube, she established goal-based buying across awareness, consideration, and action—scaling offerings like TrueView for Reach and introducing SMB-friendly creation tools.

That ad-tech pedigree matters. Instacart has been first to market repeatedly—self-serve platforms, incrementality measurement, powering other retailers' ad networks. Now competitors are studying what Instacart built and replicating it with bigger budgets. Miller faces the classic innovator's dilemma: how do you stay ahead when your playbook becomes industry standard?

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Acts 1 and 2: Building the Foundation

When Miller joined Instacart in 2021, the company was coming off the pandemic with massive attention from users, brands, and retailers. The natural starting point had been sponsored products—the basic unit of retail media advertising. But even there, Instacart differentiated early.

"One of the first areas where we tried to differentiate ourselves from other retail media networks is not just looking at attributed sales, but really looking at causal, random control and exposed groups to understand the total incrementality of Instacart sponsored products," Miller explains.

This was 2021, when most retail media networks were still pitching brands on basic attribution. Instacart was already proving incremental lift with proper test design. The platform was also self-serve from day one—unusual at a time when most retailers started with direct sales and insertion orders before building self-service capabilities.

Act 2 brought display and video formats, marrying what Miller calls "inspiration with shoppability." The company shifted to marketing objective-based buying, allowing brands to optimize explicitly toward goals like driving new-to-brand sales or total sales, rather than just managing individual cost-per-click bids.

Act 3: The Ecosystem Play

When the company launched Carrot Ads in March 2022—powering retail media networks on other e-commerce sites—it was years before other retailers announced similar platform ambitions. Now, Miller is doubling down on the company’s third act revolving around becoming the infrastructure other commerce players can plug into. 

Carrot Ads now powers retail media networks on 240-plus e-commerce sites, including Thrive Market, Hy-Vee, and Uber Eats' grocery experience.

This platform strategy is suddenly everywhere. Amazon announced its Amazon Retail Ads Service earlier last year, signing partnerships with several retailers including Macy's. Best Buy's Lisa Valentino recently outlined a vision of Best Buy as an open platform for data collaboration and audience extension. But Instacart has been executing this model for longer.

The pitch to brands is straightforward: buy once, activate everywhere. Log into Instacart ads, launch a campaign, and it serves across the Instacart marketplace plus those 240 Carrot Ads sites. For emerging brands with limited distribution, ads extend automatically as soon as their products hit shelves in new locations. For large brands managing dozens of retail relationships, it's consolidated buying with consistent measurement.

"This helps smaller brands with limited distribution get all of that opportunity they possibly can," Miller notes. "And for large brands, it's so much easier to have a single place to buy and measure and have consistent measurement."

And the pitch to retailers is not just a plug-and-play ad server, but the opportunity for retailers to tap into Instacart’s national advertiser demand. This is a significant benefit for retailers looking to grow their ad revenue after the initial ‘easy money’ of ad spend migrating from trade and shopper marketing funds is exhausted. Retailers can tap into this new advertiser demand “on day zero,” according to Miller. 

“Carrot Ads has really been a key part of changing the conversation with retailers and helping show that they have options,” Miller says. “They have options to share in ad revenue, and they have options to participate in retail media without investing all of that upfront cost in sales teams, R&D and bespoke tech,“ while adding that retailers can maintain their own supplier relationships through direct sales. 

Beyond e-commerce sites, Instacart has built full end-to-end integrations with platforms like Trade Desk and TikTok, allowing advertisers to use Instacart's purchase-based audiences for targeting and closed-loop measurement directly within those platforms. Miller describes it as meeting brands and agencies where they already are, rather than forcing them to adopt yet another buying interface.

Not On The Menu: Black Box Algorithms

Retail media is drowning in AI announcements. Every optimization feature gets rebranded, every algorithm becomes "agentic," and platforms are racing toward full automation. Mark Zuckerberg recently described a future where advertisers provide Meta "no creative, no targeting, no measurement"—just objectives and bank account access. 

A few weeks ago, Amazon announced its unified campaign manager with Performance+ and Brand+ capabilities that move advertisers toward less control in exchange for AI-driven optimization (I covered this in a separate post for The Drum). The advertising community is divided on whether these algorithmic systems are overall a good idea. Some see efficiency and scale. Others see a trust deficit waiting to get worse—platforms grading their own homework with even less visibility into what's actually happening.

So I asked Miller: where does Instacart stand?

She didn't dismiss automation, but she immediately emphasized trust and choice. When Instacart rolled out optimized bidding, they A/B tested it with clients first, kept manual controls available, and never forced adoption. "Choice and trust is really key," Miller said. "We're not forcing this."

Even as Instacart builds conversational AI shopping experiences, Miller insists on following consumer behavior rather than rushing ahead. "We don't want to rush to the conclusion of this is how ads work here," she said.

In-Store Retail Media: A Physical Hedge

While much of retail media fixates on digital inventory, Miller sees physical stores as increasingly critical—particularly as AI shopping agents threaten to intercept purchase intent before shoppers ever reach retailer websites.

Caper carts, Instacart's smart shopping carts with screens, are now deployed in nearly 100 cities. Wakefern recently announced that nearly 20 percent of its member stores will have Caper carts with ads enabled, joining Schnucks, McKeever's, and others.

"It literally has all of those same benefits of an online closed-loop experience in the aisles of the grocery store, which you essentially don't get with any other technology," Miller says. The carts have loyalty card information, real-time basket data, and location signals. They can recommend products based on what the shopper just added to their cart or what they bought previously.

Building ads for shopping carts required experimentation. Miller's team tested different approaches and found that shoppable display ads—promoting specific items with timely offers based on signals like aisle location—drove strong engagement and physical add-to-cart behavior.

She's keeping cards close on what's next for in-store capabilities, but emphasizes the trajectory is promising. "We're still early, but Caper has a pretty great trajectory," she notes.

What Act 4 looks like

The broader retail media landscape is fragmenting under its own weight. More than 200 retail media networks now compete for advertiser attention while brands struggle to manage relationships with an average of five to seven platforms. Growth is decelerating—15.6% in 2025 versus 25.1% in 2024, according to IAB data.

Miller believes simplification is the answer, but not the kind that removes advertiser control. She's building for a future where brands can buy in one place and activate across an entire ecosystem, but where they maintain transparency into results and choice in how their campaigns run.

Unlike executives rushing toward full automation, Miller is doing this with Google-bred discipline: test, measure, prove, scale. She's layering new AI capabilities on proven machine learning foundations. The company has built conversational shopping experiences, but waiting to see what consumers actually want before forcing ads into them.

“Choice and trust is really key… we’re not forcing this.”