Walled gardens are advertising ecosystems, such as Google, Meta and Amazon, that control three things at once: the inventory, the data about the people who see it, and the measurement of their own results. Their advantage is real. Logged-in user data and inventory like YouTube or Prime Video can’t be bought anywhere else.
Their limit is structural. Each garden optimizes toward what happens inside its own walls, and none of them is built to tell you how much of your budget should go to it rather than to the garden next door. That decision sits one layer above the gardens, and it’s the one Mainkore makes.
Contents
- What is a walled garden in advertising?
- Walled gardens vs. the open web
- What walled gardens do better than anyone else
- The structural limit: every walled garden optimizes within its own ecosystem
- The decision that sits above the walled gardens
- Walled garden optimization vs. cross-ecosystem decision
- What this looks like in a real campaign
- Five questions to ask before moving budget in or out of a walled garden
- FAQ
What is a walled garden in advertising?
A walled garden is a closed advertising ecosystem in which the same company owns the media, the audience data and the reporting. You buy its inventory through its own tools, under its own rules, and you see the results through its own measurement.
The best-known examples work in a similar way. Google gives access to search and YouTube through its own buying tools, including Google Ads and DV360. Meta sells Facebook and Instagram inventory using data from its logged-in users. Amazon combines its retail purchase signals with its own streaming inventory, such as Prime Video and Fire TV, through Amazon DSP.
What makes them “walled” isn’t their size. It’s that user-level data generated inside generally stays inside, and the advertiser works with what the garden chooses to show.
Walled gardens vs. the open web
The open web is inventory from thousands of independent publishers, bought programmatically through exchanges and DSPs. Walled gardens sell only their own inventory, with their own data, and measure it themselves.
The trade-off is well known. The open web offers diversity of reach and more room for independent measurement, but with more fragmented data about the user. Walled gardens offer much stronger identity data and a closed measurement loop, but with less visibility from outside. Most brands use both, which is exactly why someone has to decide the balance between them. It’s one of the reasons there are five different ways to buy media, not one.
What walled gardens do better than anyone else
Walled gardens have advantages no independent player can replicate: first-party data on logged-in users at massive scale, and inventory that only exists inside them. Pretending otherwise isn’t a serious argument.
If your customers buy on Amazon, Amazon knows more about their purchase behavior than any external system. If your audience watches YouTube, YouTube is where that attention is. And because the garden sees both the ad and the action inside its own ecosystem, it can close the measurement loop in a way the open web struggles to match.
Mainkore’s position is simple. These advantages are real, and a serious media strategy uses them. The question isn’t whether to buy in walled gardens. It’s who decides how much, and on what basis.
The structural limit: every walled garden optimizes within its own ecosystem
The algorithm inside a walled garden is excellent at spending the budget you give it. It isn’t designed to tell you whether that budget would work harder in another ecosystem.
This isn’t a question of intent. Each ecosystem optimizes using the signals and objectives it can observe inside its own environment, and that shows up in three ways.
Each garden optimizes for its own signal. It maximizes the result it can see and attribute, inside its own walls.
Each garden measures its own contribution. When the same customer interacts with ads across several platforms, more than one platform may attribute the same conversion to itself. As a result, platform-reported conversions can’t simply be added together to represent total business conversions.
No garden sees the others. A frequency cap in one ecosystem doesn’t know that the same person has already seen the brand repeatedly in another. How that plays out across channels is what cross-channel intelligence is about.
Each of these behaviors is rational inside the garden. Together, they mean the advertiser’s total budget has no one looking at the whole.
The decision that sits above the walled gardens
One of the most consequential decisions isn’t how to bid inside a garden. It’s how much each garden deserves right now, compared with the others. That’s an allocation decision, and it requires a view no single garden has.
This is where Mainkore operates. Mainkore is autonomous advertising decision intelligence that works above the platforms it’s connected to: DSPs such as Adform, DV360, The Trade Desk and Zemanta, and platforms such as Meta, TikTok and YouTube. It doesn’t compete with walled gardens for inventory, and it doesn’t replace their algorithms. Each garden keeps optimizing inside its walls, with its own data. Mainkore decides, continuously, how much budget each garden gets and toward which objective, and it can also work with the advertiser’s own first-party data.
Each of those decisions weighs more than 200 variables, is made in around 20 milliseconds and runs 24/7, drawing on learning from more than 12,000 campaigns.
Seen this way, having no proprietary inventory isn’t a gap in the model. It’s part of the model: a system with no inventory of its own has no inventory of its own to favor.
Walled garden optimization vs. cross-ecosystem decision
The difference between a walled garden’s algorithm and Mainkore isn’t one of quality. They answer different questions.
| Walled garden algorithm | Mainkore | |
| What it optimizes | Results inside its own ecosystem | The advertiser’s KPI across ecosystems |
| Data it sees | Deep, but only its own | Signals from every connected channel plus the advertiser’s first-party data, 200+ variables per decision |
| Who measures the result | The garden itself | Measured against the KPI agreed with the advertiser |
| Question it answers | How to spend this budget here | How much budget each ecosystem deserves now |
| Who bears the risk of the outcome | The advertiser | Mainkore, as the provider, commits to the KPI by contract |
Five questions to ask before moving budget in or out of a walled garden
Before increasing or cutting investment in a walled garden, the useful question isn’t whether the platform is performing. It’s who is measuring, and who is deciding.
- Who measured this result: the platform itself or an independent source?
- How many of these conversions are also being claimed by other channels?
- What doesn’t this platform see about the same customer?
- Who decides the split between ecosystems, and how often is it revisited?
- If the overall KPI isn’t met, who answers for it?
FAQ
A closed advertising ecosystem in which one company owns the inventory, the user data and the measurement of results. Google, Meta and Amazon are the best-known examples.
No. They offer data and inventory that aren’t available anywhere else. The risk is letting each garden decide on its own how much budget it deserves, and measure its own contribution.
The open web is inventory from many independent publishers, bought through exchanges and DSPs. Walled gardens sell only their own inventory, using their own data, and report their own results.
No. A DSP buys inventory. Mainkore is autonomous advertising decision intelligence that decides how budget is allocated across the platforms and DSPs it operates on, with KPIs guaranteed by contract. More in Mainkore and DSPs.
Mainkore has no proprietary inventory. It works above the ecosystems where the advertiser already buys, using real-time signals from connected channels. The advertiser can also connect its own first-party data.
Mainkore operates above DSPs such as Adform, DV360, The Trade Desk and Zemanta, and platforms such as Meta, TikTok and YouTube, deciding how budget is allocated across them against the advertiser’s KPI.
See how Mainkore decides budget across ecosystems. Find out how much of your investment is being decided by each platform, and how much by you. Talk to us
Mainkore. The intelligence that decides above the platforms. KPIs guaranteed by contract.
