Twitter admitted to using phone numbers and emails, users provided for the two-factor authentication process to target ads.
The authentication process is a security measure that allows the company to secure accounts, but apparently, some of the data was used in Partner Audience lists and Tailored Audiences.
Tailored Audiences is an industry-standard product that lets advertisers target customers based on their marketing lists.
Partner Audiences lets advertisers use the same audiences to target ads to audiences from third-parties.
Twitter said that it matched user phone numbers and their emails by accident, and the mistake was corrected by September 17th.
The site did not give the exact numbers of affected people. It made sure that no personal data was shared with third parties or partners.
After Facebook’s Cambridge Analytica scandal, social media companies are now under scrutiny to ensure data privacy for users.