Twitter, in its statement, explained that when an advertiser uploaded their marketing list, it may have matched people on Twitter to that list based on the email or phone number that the Twitter user had provided for safety and security purposes.
The company further said that no personal data was ever shared externally with its partners or any other third parties.
Gizmodo Australia has reached out to Twitter Australia to determine how many Australians were affected and how Targeted Audiences will differentiate email addresses and phone numbers which have been provided for security purposes as opposed to advertising purposes.
Twitter says it has 139 million users that use the platform every day and are served with adverts.
Whether or not Twitter meant to use phone numbers, the effect is the same, it was using sensitive account details for ad targeting without users' knowledge or permission. Twitter said that it turned off the use of the personal information for ads on September 17.
Facebook said it had also made a strikingly similar mistake in March when it admitted to correlating phone numbers intended for security with targeted advertising.
Twitter's initiative of sharing this information will make people more cautious that this may happen with other sites too.
This language, in which Twitter calls the error, "the issue that allowed this to occur", is way too passive.
Instead, however, Twitter says it inadvertently used the information to help match users' accounts with stores they may shopped at.
The problem, however, is that Twitter doesn't know whether your information was revealed or not.
This is a method that adds a second level of security - such as getting a text message with a log-in code - to prevent malicious actors from being able to use a person's credentials.
The micro-blogging platform said that it secured Dorsey's account which became victim of "SIM swapping" or "SIM jacking" where a mobile number is transferred to a new SIM card.