Twitter has issued an apology for “inadvertently” using phone numbers and email addresses provided by users for security purposes to target advertising.

“We recently discovered that when you provided an email address or phone number for safety or security purposes (for example, two-factor authentication) this data may have inadvertently been used for advertising purposes,” Twitter said in a statement.

“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 apologise.

“We cannot say with certainty how many people were impacted by this, but in an effort to be transparent, we wanted to make everyone aware.

“No personal data was ever shared externally with our partners or any other third parties. As of 17 September, we have addressed the issue that allowed this to occur and are no longer using phone numbers or email addresses collected for safety or security purposes for advertising. 

“We’re very sorry this happened and are taking steps to make sure we don’t make a mistake like this again.”

Should Twitter be punished for this mistake? Do tech giants need more oversight to protect consumers from these ‘mistakes’?