Twitter has apologized for "unintentionally" using email addresses and phone numbers, provided by users for account security, in targeted advertising.
Twitter apologized if third-party marketers may have been able to reach specific users on Twitter based on email addresses and phone numbers, even if the user did not allow for their information to be used this way. The microblogging and social networking company said it "cannot say with certainty how many people were impacted" but that it involved users globally.
While it would not say when the issue was discovered, Twitter claimed that it had addressed the problem “as of September 17”. However, the company did not proactively contact customers directly to inform them of the breach.
In a statement, Twitter said it was "no longer using phone numbers or email addresses collected for safety or security purposes for advertising”. The company, which has its European headquarters in Dublin, also claimed that it was communicating with regulators “where appropriate” but would not confirm whether or not it had notified the Irish Data Protection Commissioner.
Europe’s General Data Protection Regulation (GDPR) states that users must be informed if data is used for a purpose other than what it was intended for. According to Twitter, it 139 million users that use the platform every day and are served with advertisements.
The system used by Twitter to enable advertisers to match their own database of customer email addresses gathered independently from Twitter with users on Twitter that use the same email address, is common among social networks. However, the issue is that this email matching was referencing addresses that users had submitted solely for the purpose of enhancing their account security by adding two-factor authentication.
Twitter explained: "When an advertiser uploaded their marketing list, we may have matched people on Twitter to their list based on the email or phone number the Twitter account holder provided for safety and security purposes. This was an error and we apologize.”
