Mastering First Party & Zero Party Data in a Post Cookie World

Introduction 

As third-party cookies weaken under privacy pressure, marketers are turning to more reliable and permission-based forms of data. First party (inferred from customer interactions) and zero party (explicitly shared preferences) data are emerging as the strategic backbone of digital marketing in 2025. 

Why First Party Data Matters 

First party data is collected directly from customers via owned channels—website behaviour, CRM records, loyalty programs, email engagement, etc. According to Segment, 78% of businesses now consider first party data their most valuable resource for personalization

Zero Party Data: Voluntary, Trust Based Insights 

Zero party data refer to the preferences customers share directly—via quizzes, polls, preference centers, or loyalty forms. Salesforce reports that 87% of customers are more willing to share their data when it promises a better experience. 

Strategic Synergy: First vs Zero Party 

While first party data captures observed behaviour, zero party data add explicit context. Brands that integrate both gain a fuller view of their audience. Shopify notes these data types complement each other to fuel personalization and accurate targeting. 

Industry Shift & Urgency 

In early 2025, a survey across eight countries found 75% of marketers heavily relied on third-party cookies in 2024—but only 25% view them as a viable alternative. Even though Google delayed the cookie phaseout, the shift toward first party and zero party data is well underway. Vogue Business notes marketers have “moved on,” focusing on trusted customer data. BCG research found companies linking all available first party data sources earned double incremental revenue per ad placement and 1.5× better cost efficiency versus limited data. 

Use Cases & Tactical Playbook 

• Personalization & Retargeting: Use browsing behaviour and purchase history to tailor offers and reengage shoppers. According to Google, first party data campaigns can deliver up to 2.9× revenue uplift and 1.5× cost savings. 

• Segmentation & Loyalty Programs: Preference centers and quizzes help refine customer segments and improve targeting precision. 

• Retail Media & RMNs: Retailers leverage first party and zero party data for ad targeting across retail media networks (RMNs). A Deloitte survey reports 64% of retailers share loyalty data with brands via privacy safe clean room technologies by end2024, enabling closed loop attribution and enhanced ROI. 

Partner with Paragon  

Looking to build a first party and zero party data engine? Paragon Digital Services partners with brands, agencies, publishers, and media networks to augment digital operations teams—designing consent driven data strategy, building unified data workflows, and delivering reliable segmentation and campaign execution. Ready to power your next phase of personalization and performance? Let’s talk.