Twitter has actually used private user data for advertising purposes for security purposes. The short message service said on Tuesday that phone numbers and email addresses for the authentication of Twitter accounts were “accidentally” used for advertising.
Thus, user data has been matched with that of advertising companies to enable targeted advertising. “That was a mistake and we apologize,” said Twitter.
The service claimed that the data was not shared with partners outside the company. How many Twitter users are affected is still unclear. The problem was resolved in mid-September.