In Britain’s Co-op shops, the screen at the self-checkout has picked up a second job. By November 2025, the convenience chain was using  15,871 screens across 2,300 stores as advertising space, from front-of-store displays to kiosks, self-service tills and the small customer-facing screens beside staffed checkouts. In October 2024, it planned to install 300 front-of-store screens. Thirteen months later it had 1,000.

Co-op is far from alone. In-store retail media, the practice of selling advertising on a shop’s own screens and surfaces, is spreading across Europe as grocers and electrical retailers rewire their shops as media networks. They are selling entrances, aisles and checkouts to brands that want to reach shoppers at the moment they decide what to buy, and trolleys are gaining screens of their own. Retail media began on websites and apps. The store is its newest channel.

The odd part is the money. The screens are arriving by the tens of thousands, yet the advertising budgets meant to pay for them have barely followed them into the store. Something is holding the budgets  back, and it turns on a question that sounds simple: what counts as a shopper seeing an ad.

The scale is real. MediaMarktSaturn now sells advertising on 53,672 screens in about 738 stores across eight markets, from Germany and Spain to Belgium, Hungary and Turkey, and claims 68 million contacts a week. Advertisers can buy the network programmatically, through the same demand-side platforms they use to buy online advertising. The network launched in Germany and Spain in October 2025 and reached all eight markets by May 2026. The pitch, as the network’s managing director Boris Prondzinski frames it, is that reach at the point of sale becomes something advertisers can plan and buy across borders.

German grocery has found a way to bring individual store owners into the same business. Three media companies, Digooh Media, Verve Retail Media Holding and EMSU, have built a Retail Media Alliance for Edeka stores that links entrance displays, in-store screens, checkout television and till coupons across more than 3,300 locations and 5,000 screens, nearly 4,000 of them in Edeka shops. Store owners pay nothing to install, run or maintain the hardware. They also gain access to advertising budgets for local promotions.

Smaller networks are converting what they already own. AVIXA’s September European roundup reported that Spar is piloting a network in Hungary and Slovenia that repositions existing screens around the shopper’s route through the store, adds hundreds of new displays, and sells the space to brands while also using it for its own marketing.

Advertisers are spending heavily on retail media, mostly outside the shop floor. WARC forecasts $200.4bn of global retail media spend in 2026, and IAB UK put the British market at £3.8bn in 2025, up 18% in a year. IAB UK’s account of that growth focuses on on-site and off-site formats, from display and video to connected TV and digital out-of-home. The shop floor itself barely features.

IAB Europe’s own buyer survey is blunter. In-store digital screens, it found, are drawing interest but still attract limited investment, and buyers named a lack of standardisation (53%) and network fragmentation (51%) as the biggest barriers to retail media growth. Those barriers bite hardest in the store, where every chain counts differently. WARC found that 73.9% of UK brands spread their retail media budgets across three or fewer networks, and that a brand cannot compare a screen in one chain with a screen in another unless both count the same way. American data show the same gap. According to EMARKETER, in-store accounted for 3.3% of US retail media spending in 2025 once Amazon is excluded.

Brands have a reason for caution. Alex Brownsell, WARC’s head of content, argues that retail media is very good at converting existing demand and weaker at long-term brand building. A screen above the cereal aisle sits awkwardly between the two: too far from the till to claim the sale with confidence, too close to the shelf to feel like brand advertising.

Retailers keep building because the aisle is the one physical medium they own outright, and it reaches people who are already deciding what to buy. The early results look encouraging, at least on the networks’ own numbers. The Edeka alliance reports that sales at a pilot store in Bayreuth rose 9%, with fresh-counter sales up as much as 20%. That’s a pilot claim from the companies selling the network, and it has not been independently tested. 

Independent research tells a more careful story. A Bayes Business School study of 12,418 shopping trips at a German supermarket chain found that shoppers using AI-powered smart trolleys spent 32% more, bought 25% more items and stayed 23% longer than those who did not. The researchers describe this as an association. Higher-spending shoppers may simply be the ones who pick the clever trolley. Heavy users, who tapped the trolley’s screen more than 20 times, bought more items and stayed longer than lighter users but spent no more money. Correlation is enough to justify a pilot. It cannot set a price, and price is where the industry is now stuck.

On 17 September, IAB Europe opened a proposed second version of its in-store measurement standard for public comment, and it rewrites the basic unit of the business. Under the first version, published in December 2024, a store without sensors counted impressions from ad plays alone: the record that a piece of content appeared on a screen. The draft moves the starting point to the people in the shop. In its own words, “Ad Play is not the right starting point for media measurement; footfall is.”

The replacement estimates an opportunity to see from six inputs: average daily footfall, the number of stores, days active, placements in each store, the share of shoppers who pass through the relevant aisle, and the campaign’s share of voice. Ad plays survive only as a figure retailers must disclose. The draft also drops sales-lift metrics and aligns sales reporting on a 28-day window. A further adjustment, for the likelihood that someone actually noticed the content, can be reported only by retailers with sensor or analytics technology, and the draft itself flags possible GDPR implications.

Most of those inputs are data a large retailer already holds, from door counters to store layouts, and the draft points to Tesco’s method of counting grocery footfall as an example. This is a consultation draft, and it may change before it becomes a standard. Its direction is already plain, and the burden lands on the systems behind the screen.

Every retail estate has a few dark screens. Under a play-based model, a dead display simply produced no plays and so, no impressions. Under the proposed footfall model, the count starts with the shoppers in the store and the placements booked, so a dead screen can still be counted unless something catches it. That something is the play log. Demoted from currency, it becomes the audit trail that shows the footfall-based number was real, and every unnoticed fault becomes inventory a brand has paid for and never received.

That changes what a retailer is buying from its AV integrator. Uptime monitoring, remote diagnostics and playback logs become evidence in a commercial conversation, well beyond their old role as maintenance tools. Placement data, meaning which screen sits in which zone and which aisle, has to stay accurate through every refit. Footfall counts must connect cleanly with the content management system so the retailer can show that a campaign ran where and when it was sold. AVIXA’s roundup made the same point in brief: once a screen joins a media network, content delivery, uptime, network management and measurement become part of the commercial offer.

Sensors are the harder part. Measuring whether shoppers noticed an ad means cameras or analytics in the store, and Germany has seen how that can go wrong. In 2017, the hypermarket chain Real ended a trial of cameras in its checkout screens across 41 stores after media reports suggested customers were being analysed without their knowledge, even though Bavaria’s data-protection authority had found the trial met legal requirements. Real said the benefit to customers had not been clear enough. At InfoComm 2026, a panel on designing retail experiences heard a related warning: the kind of recognition that one generation of shoppers expects can feel invasive to another.

There is an environmental cost as well. France’s Institut du Commerce, in a guide drawn up with brands including L’Oréal and Sephora, estimates that screens can carry up to 13 times the carbon impact of printed displays over a three-year life. A network that has to earn its keep will face hard questions about every display that cannot.

Shops are turning their shop floors into advertising space because the aisle is the one medium a retailer owns outright, at the moment a shopper decides. The appetite is real, and the hardware is already on the walls. Proof lags.

Until buyers trust what an in-store impression means, most of those screens will earn less than their owners hope, and IAB Europe’s draft shows the industry settling on footfall, placement and, where the law allows, sensing as the evidence. Every piece of that evidence runs through the AV estate. The integrators who matter in retail media will be the ones who can hand a retailer a network that proves, display by display, that it was working, played what was sold and stood where the shoppers were. Those still selling screens as shop fittings will find that someone else is selling them as inventory.