Retail media networks should work more closely with marketplaces and classifieds platforms because those platforms see shopping intent that a retailer's own data misses: what people are searching and comparing before they buy, often in categories the retailer does not sell. Partnering lets a network discover new in-market audiences and enrich its first-party segments, while its own purchase data stays the anchor for measurement.
For the technology layer, see How Retail Media Platforms Work. For definitions, see Retail Media Platform vs Retail Media Network.
Table of Contents
- Why Retail Media Networks Should Look Beyond Their Own Data
- What Marketplace Intent Adds to Retailer First-Party Data
- Four Ways Retail Media Networks Can Work With Marketplaces
- What Public Examples Show
- How a Retail Media Network Can Start: A Test-and-Learn Path
- Risks and Trade-Offs
- Key Takeaways
- FAQ
Why Retail Media Networks Should Look Beyond Their Own Data
A retail media network is built on what its shoppers bought. Purchase data shows who already buys, not who is about to start shopping, and says little about big decisions made elsewhere, like a car, a move, or a new job.
Three shifts make outside intent more valuable now:
- Off-site budgets are growing. In Canada, EMARKETER forecasts retail media ad spending of C$3.8 billion in 2026, up 14.7% year over year, with display, video, and off-site formats gaining on search.
- Off-site needs more than a customer file. Reaching new shoppers works better with fresh in-market signals.
- Brands want new-to-brand growth. Outside intent points to shoppers a network has not met yet.
What Marketplace Intent Adds to Retailer First-Party Data
A retailer knows what its shoppers bought. A marketplace knows what its users are shopping for now, from listing views, searches, and replies to sellers. Together they describe a shopper better than either alone.
| Marketplace vertical | Intent signal | How it can expand a retail media network's audiences |
|---|---|---|
| Autos | Vehicle searches, messages to dealers | Tires, maintenance, car accessories |
| Real estate and rentals | Property searches, viewing requests | Furniture, appliances, home improvement |
| Jobs | Job searches and applications | Workwear, commuting, relocation |
| General buy and sell | Category browsing, replies to sellers | Upgrade buyers, accessories, protection plans |
The table is illustrative, not a measured result. It shows how life-event intent on marketplaces can open new segments in a retailer's own categories.
Four Ways Retail Media Networks Can Work With Marketplaces
- License marketplace intent segments. Pseudonymized marketplace audiences listed in DSP data marketplaces can be layered onto off-site campaigns. This is the lowest-effort start.
- Match and enrich in a clean room. A clean room shows the overlap between a network's customers and a marketplace's in-market users without sharing raw records. Overlaps become enriched segments; non-overlaps become prospecting pools.
- Buy marketplace inventory with retailer audiences. Private marketplace deals put a network's segments, or its brands' sponsored products, on marketplace listing pages where shoppers are comparing.
- Close the loop on the retailer's sales. Measure marketplace-sourced audiences against the network's own sales, new-to-brand, and incremental ROAS.
See which platforms offer off-site and clean room features in the Retail Media Platforms Directory, and set two side by side on Compare.
What Public Examples Show
Marketplaces are already packaging their intent data for outside buyers.
| Marketplace | What is publicly reported | Source |
|---|---|---|
| Kleinanzeigen, leboncoin, and Vinted | Founding members of the European Media Marketplace (July 2026), which pools first-party data and inventory from media owners, retailers, and marketplaces. Kleinanzeigen cites more than one million searches a day from people with a clear intention to buy. | Equativ |
| Kijiji | Made more than 150 first-party intent segments across 14 categories available on The Trade Desk in September 2026, built from listing views, category searches, and replies to sellers. | Media in Canada; The Trade Desk |
| Mercado Libre | Mercado Ads revenue grew 58% year over year in US dollars in Q3 2026; it applies marketplace data to social and streaming partners, including TikTok and Netflix. | Mercado Libre Q3 2026 results |
Marketplaces also run large ad businesses of their own. eBay reported advertising revenue of $1.993 billion in 2025, up 22%. Marketplaces that already sell ads have the data pipelines a partnership needs. Track new announcements on News & Studies.
How a Retail Media Network Can Start: A Test-and-Learn Path
Treat marketplace partnerships as a hypothesis to test each quarter, not a fixed plan. A practical sequence:
- Find the gaps. List life events and categories where the network's signals are thin, such as moving or buying a car.
- Start with licensed segments. Add marketplace segments to a few off-site campaigns first.
- Run a clean room match. Size the overlap with one partner and prospect into the rest.
- Test small, with holdouts. Compare campaigns with and without marketplace signals on the network's own sales.
- Package what works. Turn winners into named audiences and deals for brands.
- Build privacy in. Use consent, pseudonymized IDs, and clean rooms. In Canada, design for PIPEDA from the start.
For terms like clean room, PMP, and incrementality, see the FAQs and the primers in Resources.
Risks and Trade-Offs
- Signal freshness. Marketplace intent decays fast. Check how often partner segments refresh before paying for them.
- Measurement gaps. Many marketplace transactions finish offline, so judge partner data on the network's own sales and incrementality tests, not marketplace clicks.
- Privacy and trust. Keep matching inside clean rooms and partners' consent terms.
- Overlap with partners. Marketplaces also sell ads to the same brands. Agree up front who sells what.
Key Takeaways
- Retailer data shows what shoppers bought. Marketplace data shows what they are shopping for now.
- Marketplace intent expands a network's audiences into life events it rarely sees.
- The four routes are licensed segments, clean room matching, buying marketplace inventory, and closed-loop measurement on retailer sales.
- Start with licensed segments and small holdout tests, then package what works.
- Freshness, privacy, and offline transactions are the main constraints.
Browse the current list: Retail Media Platforms Directory. To weigh two platforms for off-site and clean room features, use Compare.
FAQ
Why should a retail media network work with marketplaces?
Marketplaces and classifieds sites capture shopping intent before purchase, often in categories a retailer does not sell. A retail media network can use it to find new in-market shoppers and enrich its own first-party segments.
How is marketplace intent data different from retailer first-party data?
Retailer data shows what people bought. Marketplace data shows what they are considering now, often vehicles, homes, jobs, and second-hand goods.
How can a retail media network use marketplace audiences without sharing raw customer data?
Through licensed segments in DSP data marketplaces, or by matching in a data clean room with pseudonymized IDs. Neither side sees the other's raw records.
Are marketplaces already sharing intent data with advertisers?
Yes. Kleinanzeigen, leboncoin, and Vinted joined the European Media Marketplace in July 2026, and Mercado Ads applies its marketplace data to advertising on social and streaming partners, including TikTok and Netflix.
Where can I compare retail media platforms that support off-site and clean room partnerships?
Browse the organised directory on this site: Retail Media Platforms, or set two side by side on Compare.