First-party data is information you collect directly through your own touchpoints — your website, your store, your email list, your customer-service interactions. It's distinct from third-party data (audience segments bought from data brokers, pixel-derived behaviour Meta and Google used to share with you) and second-party data (a partner brand's first-party data).
Why it suddenly matters
iOS 14.5 (App Tracking Transparency) and the deprecation of third-party cookies in browsers have collectively wiped out 40-80% of the user-level signal advertisers used to enjoy via the Meta Pixel and similar tools. First-party data is what's left — and it's what every modern audience-building, attribution and email playbook is now centred on.
What to collect
- Email + phone at checkout, with consent for marketing use
- Order history, AOV, return-customer flag, days-since-last-order
- Site behaviour (page views, add-to-carts) tied to a logged-in or cookied user
- Newsletter signups + content downloads with email + intent context
- Survey responses (kust_kuulis / 'how did you hear about us')
How to use it
- Upload customer lists to Meta as the source for value-based lookalikes (much stronger than pixel-derived ones post-iOS)
- Send hashed identifiers to Meta and Google via their server-side APIs (CAPI, Enhanced Conversions) to reconstruct the conversion signal the pixel lost
- Email + SMS retention via Klaviyo to harvest the LTV that paid acquisition unlocked
- Cohort analysis on first-party purchase data to know which acquisition channels actually produce repeat customers