McKinsey's latest commerce media analysis documents a structural shift: brands winning in retail media are building full-stack architectures — owned direct channels, marketplace advertising placements, and first-party data integration — rather than betting on a single platform. According to the McKinsey study, this three-layer approach delivers measurably better return on ad spend and customer lifetime value than channel-isolated strategies.
The mechanism is data continuity. A customer who clicks a TikTok ad, browses an Amazon listing, then receives a follow-up email from the brand's owned list represents three touchpoints. Without infrastructure connecting those layers, each interaction is blind to the others. McKinsey found that brands integrating first-party data across owned and marketplace channels can attribute revenue more accurately, suppress wasted ad spend on existing customers, and tailor creative by purchase history rather than demographic guesses.
This works because marketplace ads and owned channels solve different problems. Marketplace placements — Amazon Sponsored Products, Walmart Connect, Instacart ads — capture high-intent search traffic at the point of purchase. Owned channels — email, SMS, direct site — allow retention messaging, replenishment reminders, and margin-preserving repeat purchases without platform fees. First-party data is the connective tissue: a customer's marketplace purchase triggers an owned-channel welcome series; an email click informs which marketplace keywords to bid up. McKinsey's analysis showed that brands operating this stack reduce customer acquisition cost by 15-30% while increasing repeat purchase rate, because they stop re-acquiring customers they already own.
The small physical-product brand steal is a scaled-down version of the same three layers. Start with a marketplace where your customer already shops — Amazon if you sell consumables, Etsy if you sell craft goods, eBay if you sell collectibles. Run modest sponsored product ads there: $10-$20 daily, targeting your top three keywords. Simultaneously, build an owned email list by inserting a product card in every shipment: "Get 20% off your next order — text JOIN to [number] or scan this QR code." Use a simple ESP like Klaviyo or Mailchimp (free up to 500 contacts) to send a three-email welcome series, then a monthly replenishment or new-product email. The data layer is basic: tag email subscribers who came from marketplace orders, and exclude them from your marketplace retargeting campaigns. You now have attribution (you know which channel drove the first sale), suppression (you stop paying to re-acquire owned customers), and a margin-rich repeat channel. Total monthly cost: marketplace ad spend plus $0-$45 for email software.
The broader lesson is platform diversification without data fragmentation. McKinsey's documentation confirms that brands treating each channel as an island — running Amazon ads with no follow-up, collecting emails with no suppression list, posting on TikTok with no purchase tracking — leave 25-40% of potential revenue on the table. The full-stack approach is not about spending more; it is about connecting what you already do so each dollar works harder across the customer journey.