Adapting Marketing Strategies in the Post-Cookie Era

As third-party cookies disappear, marketers turn to privacy-friendly alternatives like contextual targeting.
Explore how first-party data and content-based ads are shaping the future of digital marketing.

The Decline of Third-Party Cookies and the Rise of Contextual Marketing

For years, performance marketers have heavily relied on third-party data to run personalized ad campaigns. By tracking user behavior across websites and mobile apps, marketers could understand consumer needs and strategically re-engage them with ads — ensuring their products stayed top-of-mind.

However, with major tech players like Apple and Google taking a strong stance on user privacy, the marketing landscape is rapidly shifting. The ability to track and target individuals through third-party cookies is becoming increasingly restricted.

What Are Cookies?

Cookies are small data files — typically less than 4KB — that store information about a user’s interactions with a website.
They help personalize the user experience by acting as a bridge between the user and the site.
Source: Doosan Encyclopedia

Despite their tiny size, these cookies have shaken even the biggest names in tech — including Meta.

Apple’s introduction of App Tracking Transparency (ATT) required apps to obtain user consent before collecting tracking data. Unsurprisingly, most users opted out. This significantly undermined Meta’s ability to serve personalized ads, leading to a 3.3 percentage point drop in its share of the online ad market in 2022.

Chapter 1:
Types of Data and How They’re Used

While cookies log user activity, data is often categorized based on who collects it and how:

• Zero-party data: Provided directly by the user (e.g., surveys)

• First-party data: Collected directly by a company from its own users (e.g., website behavior)

• Second-party data: Another company’s first-party data purchased or shared under agreement

• Third-party data: Aggregated from multiple websites or platforms, often without direct user interaction

This classification is intuitive — the more indirect the source, the more complex and less transparent the data tends to be.

Zero-party data is often obtained through surveys. Because users voluntarily provide opinions and preferences, this type of data is high in quality but low in quantity, requiring effort and user trust.

First-party data, on the other hand, includes behavior from users visiting a company’s website or app. With rising privacy concerns, many businesses are now prioritizing CRM (Customer Relationship Management) systems that utilize this data to optimize pages and retain high-intent users. As the cost of user acquisition increases, maximizing the value of these visits has become mission-critical — especially in the absence of third-party cookies.

Second-party data often comes from partners who exchange or sell user data, typically under user consent agreements. However, these arrangements can still raise concerns — users may not fully understand how or where their data is shared, and headlines about data misuse continue to erode trust.

Third-party data is the most opaque. It’s compiled from multiple sources, often without direct user input. Techniques like retargeting, where ads “follow” users based on previous searches or visits, rely heavily on this type of data. These methods, while effective, raise serious privacy issues.

This is why companies like Google and Apple have announced plans to phase out third-party data collection entirely.

Chapter 2:
Searching for a New Path Forward

As we've seen, zero- and first-party data are valuable but limited in scale, while second-party data often carries ethical concerns. For new brands, all three types can be difficult to access — making third-party data a go-to for increasing reach. But this path is closing quickly.

Although new technologies are emerging to balance privacy with personalization, a full replacement for third-party cookies has yet to be developed.

So, how can marketers continue to reach relevant audiences? One promising answer is contextual marketing — a strategy that serves ads based on the content a user is currently viewing, rather than past behavior.

Unlike behavioral targeting, contextual marketing places ads alongside related keywords or thematic content, reaching users who are likely to be interested based on real-time content signals, not individual tracking.

For example, ads in KakaoTalk Open Chat or Naver Open Talk — both interest-based communities — are now gaining traction as high-engagement, intent-driven ad placements. Because users actively participate in these spaces, aligning ad messaging with group interests can drive far greater ROI than broad, untargeted campaigns.

Beyond contextual targeting, we’re also seeing growth in:

• SEO-driven search marketing

• Retention marketing using first-party data

• Content marketing that strengthens brand perception and trust

While the end of third-party cookies has disrupted the status quo, performance marketers are no strangers to change. The industry has always adapted — through new platforms, creative formats, and better measurement tools.

Just as a 4KB cookie rattled giants like Meta, a new wave of innovation will drive the next era of digital advertising. Marketers who return to fundamentals — serving the right message to the right audience — will navigate this transition with confidence and success.