Browser Fingerprinting: The Cookie's Stealthy Successor
Original: Fingerprints are the new cookies
Why This Matters
Fingerprinting is harder to block and easier to monetize than cookies—regulators lag behind.
Browser fingerprinting lets advertisers track users persistently across devices and sessions—without cookies. Google's 2024 policy shift now explicitly permits fingerprinting in its ad products, after years of promising a privacy-first alternative.
When Google pledged in 2020 to phase out third-party cookies, it framed the move as a privacy milestone. Five years later, the outcome looks different: cookies survived, Google's Privacy Sandbox replacement flopped amid antitrust scrutiny, and the company quietly opened its ad platform to device fingerprinting instead.
Fingerprinting works by harvesting signals your browser already broadcasts—OS type, language settings, IP address—then adding data gathered via JavaScript: screen resolution, installed fonts, GPU rendering quirks, and more. Individually mundane, combined they form a near-unique identifier that persists across incognito tabs, VPNs, and cookie clears.
The article demonstrates this live: a script assigns visitors a consistent nickname that survives cache clears and private browsing. Only disabling JavaScript or using Safari (particularly iOS/macOS 26+) or Firefox—which extend their privacy definitions beyond Chrome's baseline—meaningfully disrupts it.
The broader concern isn't targeted ads. It's that fingerprint-linked behavioral profiles, sold to data brokers, can be cross-referenced with account data purchased from publishers under standard privacy policies—building detailed dossiers without any single breach. Chrome and Edge, the author notes, draw the line at tab isolation and go no further. Safari and Firefox push harder on fingerprint surface reduction. Chrome holds roughly two-thirds of the browser market.