Twitter has removed a privacy feature that allowed all users to stop sharing some private information with advertisers. The setting prevented Twitter from sharing information like the ads you saw or interacted with and the tracking identifier for your phone. For most users, that information will now be shared by default and can’t be turned off.
The shared data is used to show the efficacy of advertising on Twitter, the company says. It helps Twitter prove that people are actually watching, interacting with, and otherwise seeing the ads that advertisers are paying for, which helps the company “continue operating as a free service.”