Commerce media has spent years expanding beyond retailers’ owned and operated properties. But getting inventory onto social platforms, connected TV (CTV), and the open web doesn’t create demand on its own. Advertisers need a reason to use it.

That’s particularly true on social, where just $1.3 billion will flow from retail media networks (RMNs) this year, representing less than 2% of retail media ad spending, according to EMARKETER’s forecast.

“As we've watched the market evolve, it's become pretty clear that building more inventory and more supply doesn't automatically guarantee advertiser demand, especially in channels where brands have established buying partners and workflows,” said EMARKETER principal analyst Sarah Marzano, in a talk at Advertising Week New York on Monday.

For Instacart, the opportunity is to make advertisers’ existing media buys more effective rather than force them into another buying platform. Its partnership with Pinterest offers a test case for that strategy, combining Instacart’s purchase data with a platform built around product discovery.

Commerce data has to prove its incremental value

Instacart’s advantage comes from seeing ecommerce purchases across thousands of retailers rather than within a single retailer’s ecosystem.

“One campaign reaches millions of consumers across thousands of retailers across multiple platforms,” said Tim Castelli, vice president of global advertising sales at Instacart, in the Advertising Week New York session.

Instacart works with 2,200 retailers on its marketplace and powers ads on more than 310 ecommerce sites, giving it a broad pool of first-party purchase data, according to Castelli.

But expanding off-platform means proving Instacart adds incremental value rather than simply providing better attribution for shoppers who would have purchased anyway.

Between 70% and 71% of Instacart’s audiences shop for ecommerce only through Instacart, and its work with partners like Circana has shown high levels of incrementality versus in-store shoppers, Castelli said.

Meeting advertisers where they already buy

The proliferation of RMNs has created more ad environments for advertisers to choose from and assess. Instacart’s answer to this fragmentation is to bring its audiences into platforms buyers already use.

Instacart is also prioritizing self-service integrations that let advertisers use its data from within their existing workflows.

“Self service, I think, is the future here,” Castelli said. “If we can take our data and be in these platforms, [advertisers can] go on to their seat in The Trade Desk, build the audiences, and use that to buy media.”

That approach is particularly important as advertisers consolidate their retail media partnerships.

“People are doing less partners and going deeper,” said Castelli.

The winners, he argues, will connect commerce data with media buying without creating additional friction.

Pinterest connects discovery to purchase

Pinterest brings a different piece of the shopping journey to the partnership.

Pinterest pairs scale with shopping intent. The platform has about 640 million monthly active users, more than half of whom are Gen Z, according to Lee Brown, Pinterest’s chief business officer, who spoke at Advertising Week New York. Those users conduct about 80 billion searches per month, many with commercial intent.

Food is Pinterest’s largest category, making Instacart a natural partner for turning that discovery into purchases.

Early results suggest the partnership can expand advertisers’ audiences. Campaigns across six or seven brands have seen about 85% incremental audiences compared with data those advertisers traditionally used on Pinterest, according to Castelli.

Creative that includes Instacart branding is also generating three to four times the clickthrough rate, he said.

“It's almost like a buy signal,” Brown said.

Breaking down budget silos may be the harder challenge

While the technology may be getting easier, changing how advertisers organize budgets is another matter.

Social, ecommerce, programmatic, and national media have traditionally sat with different teams, making it difficult to treat commerce data as an enterprise-wide asset.

“The only thing that stands in the way is [the assumption] that that's not my budget, that's not my decision, my silos,” Castelli said.

That is slowly changing as brands move toward more omnichannel structures and agencies integrate ecommerce capabilities into broader media planning.

“If people are looking at us, or frankly, any retail media network as performance only…they're missing the future of what's possible,” Castelli said.

That future could become even more important as AI agents handle more transactional shopping tasks. But Pinterest doesn’t expect consumers to outsource discovery itself.

“They love the joy of shopping, and so we don't think any agent is going to replace that joy of shopping because that's what humans love to do,” Brown said.

For Instacart and Pinterest, the opportunity lies in eliminating the friction that comes after discovery.

“We need to make it easier for consumers to close that transaction,” Castelli said.

This was originally featured in the Commerce Media Weekly newsletter. For more marketing insights, statistics, and trends, subscribe here.