Cookies were built to prevent tracking
Did you know web cookies were designed to prevent tracking?
· 29-sec read
In mid-1994, Netscape engineer Lou Montulli was asked how a shopping-cart server could remember a user. He rejected a popular proposal for a unique ID in every browser, because it could follow people across all websites, and instead designed a value that a site sends and that goes back only to that site. He took the name from 'magic cookie', a term from a college operating systems course. Third-party cookies on embedded ads were the loophole he hadn't foreseen.
Popular version vs. what really happened
Popular version
Popular version: cookies were invented for ad tracking.
What really happened
Reality: they were designed to avoid cross-site tracking; ads exploited third-party cookies later.
Why it matters
Design for the abuse case: embedded third-party content turned a privacy-minded design into the web's tracking backbone.
Sources
High confidenceChecked October 20, 2026.
- The reasoning behind Web Cookies (Lou Montulli's blog, 2013) montulli.blogspot.com