Zero-Party, First-Party, Second-Party, and Third-Party Data: What's the Difference?
In recent years, internet users have gained meaningful legal protection over their personal data. Regulations like the EU's GDPR and California's CCPA have raised the compliance bar significantly, and the era of third-party cookies is drawing to a close as Google Chrome moves toward withdrawing support for them.
As a result, marketers, advertisers, and agencies have been rethinking their data strategies — finding ways to deliver personalized advertising without leaning on third-party data, which had long been the default in programmatic advertising.
While many organizations have turned their attention to first-party data, another category has been gaining traction: zero-party data.
This guide explains what zero-party data is, why it matters in today's privacy-first environment, and how it compares to first-party, second-party, and third-party data.
Key Points
- Zero-party data is data that customers own and willingly give to brands — for example, to personalize their experience or receive something of value in return.
- Zero-party data helps align a brand's offering with a customer's current needs and can accelerate growth in a more targeted direction.
- Examples of zero-party data include information collected via newsletter sign-ups, calculators, quizzes, and surveys.
- To collect zero-party data, organizations must have privacy and data processing policies that comply with applicable regulations such as GDPR and CCPA. Marketers can use customer engagement platforms to collect this data and enrich single customer views (SCVs) within customer data platforms (CDPs) or customer relationship management (CRM) systems.
- Marketers use zero-party, first-party, and third-party data to build audiences for ad campaigns.
- The key distinction between zero-party and first-party data is intent: zero-party data is proactively submitted by a customer to improve their own experience (e.g., to receive more personalized recommendations), while first-party data is passively collected through interactions such as newsletter sign-ups or browsing behaviour.
What Is Zero-Party Data?
Zero-party data is data that customers willingly give to brands — intentionally and proactively. Users typically share zero-party data to improve their experience on a website or mobile app, often through polls, surveys, or preference forms.
Source: Forrester
The term "zero-party data" was coined by Forrester Research, a firm that champions customer-centric business practices. In 2020, Forrester highlighted that brands would need to shift focus toward data shared directly by their customers, given the tightening of privacy laws including GDPR, CCPA, and Vermont's data broker registration law.
Typically, customers expect something of value in return for sharing their data — an e-book, a report, a curated e-mail newsletter, a discount, or simply a better, more personalized experience. Collecting this kind of direct, permission-based information gives advertisers a more complete picture of a customer's preferences, challenges, goals, and interests.
Why Is Zero-Party Data Important?
Effective advertising depends on knowing who you're talking to. By collecting data directly from consumers about their interests and preferences, advertisers can serve more relevant ads. But zero-party data matters for several additional reasons:
Zero-party data is more trustworthy than third-party data — customers who freely share personal information with a business, and understand it will be used for personalization or to improve their experience, are more likely to provide honest, actionable data.
Personalization and customer experience — customers who are already familiar with a brand's products or services can voluntarily submit preference data to further customize their recommendations and interactions.
Segmentation — organizations collecting zero-party data can design intake forms specifically to capture the information needed for meaningful audience segmentation.
Data clean room collaboration — companies can share anonymized zero-party data within a data clean room environment and analyze combined data sets to refine targeting strategies or develop new campaigns.
Marketing consent — when a potential customer submits their data, they can simultaneously indicate which contact channels they're comfortable with: e-mail, phone, SMS, and so on.
Brands collect information on customer preferences to send more personalized recommendations. Source: Forrester
Direct communication with the customer helps brands prepare more relevant offers.
Current trends in AdTech and MarTech are reinforcing the value of zero-party data. Brands, publishers, and agencies are building data acquisition scenarios into their marketing strategies to capture more of it. As consumer privacy awareness continues to grow, zero-party data will become an increasingly important foundation for building genuine, individualized customer relationships.
Zero-Party Data Examples
There are many mechanisms for collecting zero-party data. Simple forms attached to newsletter sign-ups, calculators, quizzes, and surveys all qualify — essentially any touchpoint in the marketing funnel that captures user-submitted information.
Brands typically offer something in return. Incentives can take many forms: free newsletters, e-books, discounts, exclusive community access (such as a private Facebook group), free consultations, or simply better-matched content and product recommendations.
How To Collect Zero-Party Data
Marketers use a variety of strategies to gather information directly from users. However, organizations must also establish appropriate privacy and data processing policies before collecting, storing, or processing zero-party data. European organizations are governed by GDPR; businesses operating in California must comply with CCPA.
When drafting these policies, organizations should be prepared to answer the following questions:
- What personal information is being collected?
- How is the information collected?
- Why is the data collected?
- How will the information be used?
- Who will have access to the information?
- What choices do users have?
- Can users review or correct their personal information?
- What security measures protect the information?
- How long will the organization honour its privacy policy?
- Who is accountable for the organization's privacy practices?
These policies should be prominently displayed — for example, in the website footer.
On the technology side, marketers can use customer engagement platforms to collect zero-party data and enrich single customer views (SCVs) within customer data platforms (CDPs) or CRM systems.
What Is First-Party Data?
First-party data is collected directly from people who have interacted with a brand — including customers, subscribers, and website visitors.
Common examples of first-party data include:
- Purchase history and transaction data — products purchased, order values, and frequency, typically collected through e-commerce platforms or point-of-sale systems.
- Personal information — names, postal and billing addresses, email addresses, and phone numbers, collected through e-commerce sign-ups or offline transactions.
- Account and download data — information about users who have created an account, downloaded a digital product, or made a purchase, often stored in a CRM system.
- Behavioural data — pages visited, videos watched, and other content interactions, typically captured through website and mobile app analytics tools.
First-party data can originate from both online and offline sources.
How Is First-Party Data Used in Programmatic Advertising?
Data has been central to programmatic advertising from the outset. Advertisers collect data, segment it, build audiences from it, and use those audiences to power targeting, measurement, attribution, and analysis.
The goals are familiar: convert visitors into customers, upsell to existing customers through audience-targeted and retargeting campaigns, identify which channels and creatives deliver the best ROI, and gain insight into consumer behaviour.
Historically, advertisers relied heavily on third-party data for audience targeting and measurement, given its ready availability through third-party cookies and data brokers. The shifting privacy landscape has made that approach increasingly difficult, prompting advertisers, agencies, and publishers to lean more heavily on first-party data.
A practical example: companies in the programmatic space use first-party identifiers — such as an email address from a CRM or CDP — to generate a universal ID. That ID is then used to recognize the same person across the web and deliver relevant, targeted ads. In this way, universal IDs are stepping into the role previously filled by third-party cookies.
What Is Second-Party Data?
Second-party data — sometimes called partner data — is data gathered by one company and sold or exchanged to another, usually a business partner serving a similar audience.
A straightforward example: a travel agency and a hotel chain. Both organizations serve overlapping customer segments and could exchange data to show ads to shared audience groups, or one could pass data to the other to enable more precise campaign targeting.
Second-party data allows companies and advertisers to reach an additional, previously untapped pool of potential customers. Because those individuals are either already customers of the partner or have signalled intent to become one, second-party data can be competitive with first-party data in terms of quality.
What Is Third-Party Data?
Third-party data is collected indirectly from consumers and is generally considered the least valuable of the data types. It is assembled — or "stitched" — from multiple sources, including commercial, academic, non-profit, and governmental websites.
How Is Third-Party Data Created?
In the AdTech ecosystem, publishers, e-commerce merchants, and app developers who want to monetize their audiences add third-party tracking scripts to their websites or tracking SDKs to their apps, then pass audience data to data brokers (marketplaces or exchanges) and data management platform (DMP) vendors.
Data brokers stitch these data sets together into audience segments organized around interests, purchase preferences, income groups, demographics, and more. They can further enrich these segments with information from offline data providers — credit card companies, credit scoring agencies, and telcos.
The primary advantage of third-party data is scale: advertising campaigns powered by third-party data can reach a far broader audience than what zero-party, first-party, or second-party data alone could support.
Examples of third-party data include:
- Browsing history
- Content interactions
- Purchase behaviour
- Profile information entered by the user (e.g., gender, age)
- GPS location data
Comparing Zero-Party, First-Party, and Third-Party Data
The table below compares these three data types across four dimensions: relevance and transparency, accessibility, competitiveness, and reach.
| Zero-Party Data | First-Party Data | Third-Party Data | |
|---|---|---|---|
| Relevance and transparency — How closely connected is the audience to the advertiser's target, and how transparent is data quality? | Highly valuable — submitted directly by consumers who want to be understood. | Composed of existing customers or people who have actively engaged with a brand, meaning the audience usually overlaps with the advertiser's target. | Because data is aggregated from many sources, the direct connection between advertiser and user is diluted. Relevance is often low. |
| Accessibility — How easy is it for an advertiser to collect? | Collected directly from the brand or publisher's own website or app. | Collected directly from the brand or publisher's own website or app. | Once an integration with a DMP or data broker is in place, data sets can be purchased on demand with no additional implementation required. |
| Competitiveness — What competitive advantage can this data provide? | Submitted directly by prospects, customers, or users — enabling content personalization, lookalike audience creation, advanced analytics, and improved user experience. | Exclusively available to the brand or publisher, making it useful for high-converting activities like ad and content personalization. | Widely accessible to many companies simultaneously, which reduces its competitive value. |
| Reach — How many people can an advertiser reach? | Limited to the group of users who have directly shared data with the publisher or brand. | Limited to website visitors and existing customers. | Data brokers and DMPs aggregate data from many partners, giving them coverage on nearly every user on the internet. |
Zero-Party Data vs. First-Party Data: What's the Difference?
When both data types can originate from the same person, the distinction can seem subtle. The key is the reason a consumer shares the data.
Zero-party data is submitted proactively by users who want a more personalized experience — for instance, content recommendations tailored to their stated preferences. First-party data, by contrast, is collected through interactions with a brand or publisher — a name and email address captured during a newsletter sign-up, for example.
The practical effects of each differ as well. Zero-party data can sharpen ad targeting by giving advertisers direct insight into what customers currently want and need. If a user completes a survey indicating they prefer basketball shoes over running shoes, that signal can immediately inform which ads are served to them — a level of specificity that passively collected first-party data rarely achieves on its own.
As privacy regulations tighten and third-party signals continue to erode, the combination of zero-party and first-party data is becoming the practical foundation for sustainable, consent-based advertising. Organizations that invest in building the infrastructure — and the value exchange — to collect it will be better positioned for what comes next.