First-party data
First-party data is information you collect directly from your own customers and visitors, sign-ups, purchases, product usage, survey answers, email engagement. You own it, you gathered it with consent, and no one else has the same set. It contrasts with third-party data bought from outside aggregators, which is increasingly restricted and unreliable as browsers kill tracking cookies.
For a founder this is your most defensible growth asset. As ad-platform targeting degrades, the businesses that win are the ones with a rich first-party picture of who their customers are and what they do. It powers better onboarding, sharper email segments, lookalike ad audiences built from real buyers, and personalisation that doesn't feel creepy. The practical move is to capture it deliberately and cleanly from day one, store it in one place, keep consent tidy, and treat it as the foundation every other growth lever stands on.