Last updated: 2026-04-28. The 30-second answer: customer data drives targeted advertising in three layers. First-party data (your CRM, product, and site behavior) is the foundation; you own it, it is consented, and it travels through the privacy storms. Second-party data (partner-shared, with consent) sharpens segments. Third-party data (intent providers, identity graphs) is the multiplier that lets you reach the right account before they fill out a form. The 2026 reality: brands that lean on first-party plus an account graph plus intent surges out-perform brands that still rely on cookie-pixel audiences alone. This piece is the playbook from data capture to ad-platform activation, with payment-data, behavioral, firmographic, and intent inputs all named.