When Harvard Business School's Benjamin Edelman researched these hidden mechanisms in 2010, he found that the "enhanced features" option of a product called Google Toolbar—a plug-in for Microsoft's Internet Explorer web browser that lets users search without having to go to google.com—transmits to the company "the full URL of every page view, including searches at competing search engines." Edelman discovered that it was "strikingly easy" to activate this option but impossible to disable it. Even when a user specifically instructed that the toolbar be disabled, and even when it appeared to be disabled because it had disappeared from view, the toolbar continued to track browsing behavior.

Shoshana Zuboff, The Age of Surveillance Cap…, loc. 414