Quote Investigator:

Richard Serra? Carlota Fay Schoolman? Steve Atkins? Tom Johnson? Andrew Lewis? blue_beetle? Tim O’Reilly?
 
 Dear Quote Investigator: For decades the most powerful mass medium has been television. The internet has dramatically shifted our access to information. Nowadays, society reflects upon itself by using internet search engines. Yet, both of these fundamental channels of communication, access, and synthesis are primarily supported by advertising. A pithy expression explicates the resultant skewed perspective:
 
 You’re not the customer; you’re the product.