In the face of growing privacy regulation and continued signal deprecation, some have argued that identity in advertising was never essential to begin with. The claim is not that ads would stop running without it, but that identity was a convenient construct we layered onto marketing as it modernized. Useful at times, perhaps, but ultimately unnecessary. Content would still be consumed. Brands would still grow. Media would still transact. The system would keep moving.
I agree with part of that premise. If identity disappeared tomorrow, ads would still run. What would change is something far more consequential: our ability to understand which parts of our effort actually worked, and why.
They claim marketers can simply revert to broad context or old measurement techniques without identifying consumers. This rebuttal makes the opposite case: identity remains a critical foundation for effective advertising in the modern era. Far from preserving “old buying habits,” an identity-based approach powers accurate measurement, continuous optimization, cross-channel integration, and even privacy compliance. The following evidence-backed points demonstrate why a durable identity layer is more indispensable than ever.
Measurement and Optimization
Advertising identity – the ability to recognize the same consumer across channels – is essential for accurate measurement and in-flight optimization.
Marketers need to know during a campaign what’s working and what’s not, so they can reallocate spend and refine tactics on the fly. Without identity, they are effectively flying blind. As one industry expert put it, “measuring performance without quality consumer identification is sketchy at best.” In other words, if you can’t reliably identify who saw an ad and who converted, any optimization or ROI measurement becomes guesswork. The same Forrester Consulting study reported that with weak identity resolution, 52% of marketers struggle to prove performance and 50% struggle to optimize campaigns, underscoring that poor identity data directly undermines both measurement and real-time optimization .
Critically, identity enables in-flight course corrections by linking ad exposure to outcomes in near-real time. For example, the Association of National Advertisers’ (ANA) new cross-media measurement initiative Aquila uses a “virtual ID” to deduplicate audiences across platforms and feed granular data into media mix modeling (MMM) tools. Aquila’s leaders note that the more granular an MMM model is (i.e. built on person-level identity data), the more effective it is for marketers, allowing them to fine-tune channel mix with real consumer signals. While some suggest marketers could rely on MMM alone without user identifiers, even the IAB acknowledges MMM without identity is less precise and slower – a blunt instrument that “takes more time and can be quite expensive” compared to identity-driven attribution. In short, identity data turbocharges measurement models by turning every impression into a measurable investment, enabling truly data-driven budget optimizations while a campaign is live, not just after the fact.
Learning Loops
Critics sometimes claim that identity-based marketing clings to “old buying habits,” perhaps thinking of the cookie-fueled retargeting frenzy of the past. The reality is the exact opposite: traditional media planning without identity was based on blunt assumptions and even luck, whereas modern identity-driven marketing creates continuous learning loops and outcome-driven strategies.
Decades ago, John Wanamaker famously quipped that half of his advertising was wasted – he just didn’t know which half. In those days, advertisers bought TV, print, or radio largely on broad demographic proxies and hoped for the best. This “spray and pray” approach is what preserved old habits, relying on mass reach and repetition because there was no way to know precisely who was seeing what.
By contrast, identity data has ushered in an era of evidence-based, adaptive marketing. Marketers can now tie ad spend to actual business outcomes and refine their approach iteratively.
Consider the case of Procter & Gamble: a few years ago, P&G realized its broad, mass-targeted digital ads were largely wasted impressions, so it cut $200 million in spend and shifted to precision targeting – achieving better ROI without increasing budget. This pivot was only possible by analyzing customer-level data (i.e. an identity-based insight) to identify waste.
Today’s best marketers run “learning loops”: they launch campaigns targeted to known audience segments, measure the response by identity (conversions, sales lift, etc.), then adjust creative, frequency, and media mix in near-real time. Identity makes advertising a closed-loop system of continual improvement rather than a one-shot gamble.
As I shared on Viant’s blog, brands are moving from channel-centric buys to people-first strategies by building household-centric identity frameworks that unify their view of the consumer. This identity-centric approach creates a feedback loop: each campaign’s results inform the next, driving outcomes ever higher. Far from ossifying old habits, identity is the engine that powers innovation and agility in modern marketing.
Across Boarders
It’s a mistake to think of identity as only a “digital advertising” concern tied to cookies. In reality, identity is now the foundational backbone across virtually all channels – including connected TV, digital out-of-home, and programmatic audio/radio. As advertising has become addressable in new mediums, the same need arises: knowing whether the same person or household saw your message in different places.
Connected TV (CTV) is a prime example. CTV has exploded in popularity, but it inherited the fragmented identity landscape of streaming apps and devices. Identity delivers exceptional value in Connected TV because household-level identity brings precision and accountability to a medium once defined solely by broad reach and Gross Rating Points (GRPs). In linear TV, buyers had to accept imprecise delivery (e.g. buying age 18-49 demographic on a show) and couldn’t control who saw the ad how many times. Now, with identity, a CTV advertiser can deduplicate audiences across Hulu, Roku, and YouTube and ensure each household sees the ad an optimal number of times – avoiding overexposure and waste. By anchoring reach and frequency to deterministic IDs, marketers eliminate the old problem of one viewer seeing the same ad 20 times while another sees it zero times, which was common in the blunt GRP era.
The same identity framework extends to “out-of-home” channels that have gone digital. Digital out-of-home (DOOH) screens and digital audio platforms now offer addressability and measurement, but only if the audience can be identified (often via device IDs, logins, or inferred exposure with foot-traffic analysis).
Today’s mix of identifiers across display, retail media, digital out-of-home, and audio channels makes a coherent cross-channel strategy impossible without identity. Marketers want to know whether the person who heard their ad on streaming radio is the same person who later saw their connected billboard ad and ultimately visited their website. Without a common identity layer, each channel remains a silo. With it, brands can sequence messaging across mediums (for example, showing a connected TV ad, then a follow-up audio ad to the same individual) and measure cumulative reach without double counting.
Identity resolution has become a priority for media owners themselves. TV networks and streaming platforms are building identity graphs to support deterministic household mapping, deduplicated reach, and outcome-level measurement. As CTV has expanded across platforms, devices, and applications, inventory has multiplied while identity has fragmented. Without a unifying layer, advertisers lose frequency control, overexpose the same households, and misinterpret reach as incremental impact.
This is why many CTV publishers and media owners now participate in direct data matching with buy-side platforms, allowing authenticated subscriber relationships to be deterministically resolved to household-level identity. When those matches occur upstream, advertisers can transact against supply where identity is known, consistent, and enforceable across impressions, not inferred downstream after the fact.
Household-level identity brings precision to a medium once governed by broad demographics and GRPs. Marketers reduce waste, protect the viewer experience, and extend reach to new households instead of saturating the same ones. Identity is not an enhancement layer. It is the infrastructure that allows modern omnichannel campaigns to function as a system rather than a collection of disconnected buys.
Inefficiencies and Privacy Pitfalls
What happens when marketers lose the ability to identify audiences across devices and platforms? The system regresses.
Efficiency collapses first. Cross-device identity and frequency control are not optional optimizations. They are foundational to campaign ROI and user experience. Without the ability to recognize the same person across a phone, a laptop, and a TV, advertisers mistake duplication for reach. The same ad is delivered repeatedly to the same individual, budget is wasted, and consumers are irritated.
Identity is what turns reach into incremental reach. When frequency is anchored to a person or household, overexposure is eliminated and spend can be redirected toward net-new audiences instead of reinforcing saturation.
Perhaps counterintuitively, a loss of identity resolution can also undermine consumer privacy and preference management. Without consistent identifiers, honoring opt-outs and privacy choices becomes far more challenging. Imagine a consumer who opts out of tracking on a web browser – if the advertiser cannot recognize that same individual when they open the brand’s mobile app, the consumer may continue to be tracked or targeted, contrary to their request. A robust identity solution (especially one rooted in first-party, consented identity data) is what enables companies to propagate a user’s privacy preferences across all touchpoints.
It’s telling that in the Forrester survey, 40% of brands struggled to ensure that opt-outs and privacy controls were properly in place – a struggle tied to identity fragmentation . Marketers and publishers need to know “who is who” in order to suppress an ad or stop data processing for a given individual who revoked consent.
Moreover, leading frameworks for privacy compliance, such as consent management platforms and data clean rooms, depend on identity to function. Privacy and identity are not opposites – they are partners. Only by resolving identities with appropriate consent can marketers both respect consumer choices and continue to measure and personalize effectively.
Abandoning identity would not be a win for privacy; it would more likely lead to opaque workarounds and inconsistent enforcement of consumer rights.
Identity Is Not the Enemy of Modern Marketing
The advertising ecosystem is already fractured. Browsers behave differently. Mobile operating systems enforce different rules. And when Connected TV emerged, it failed to apply the hard-earned lessons of mobile. Instead of converging on consistent identity, measurement, and frequency standards, CTV introduced new operating systems, closed platforms, and incompatible identifiers.
Fragmentation was not reduced. It was compounded. That is exactly why investing in a durable identity layer is required, not why identity should be removed from the ecosystem.
We now have more identifiers than ever and less clarity than at any point in modern marketing because of it. Device IDs, emails, publisher IDs, platform IDs, statistical IDs. None of them mean anything in isolation. Without reconciliation, they don’t create insight. They create noise.
The argument that removing identity will somehow improve marketing ignores how identity has always operated. Contextual and publisher-based delivery do not replace identity. They still require it to control frequency, honor consent, and understand outcomes.
At this point, disbelief in identity stops being philosophical and becomes operationally irresponsible.
Ads will continue to run without identity. That was never the question.
What disappears without identity is accountability. Learning. The ability to know what worked, why it worked, and how to repeat it without waste or risk.
Identity didn’t create bad marketing. It exposed it.
Removing identity doesn’t make the ecosystem healthier. It makes it opaque, inefficient, and historically regressive. We already know what that world looks like. We built better tools precisely because it failed.