Users in India and elsewhere received the pop-up message late Wednesday, which said that "the control you have over what information Twitter shares with its business partners has changed."
"Specifically, your ability to control mobile app advertising measurements has been removed, but you can control whether to share some non-public data to improve Twitter's marketing activities on other sites and apps," read the pop-up.
An option in Twitter's privacy settings called "Share your data with Twitter's business partners" used to let users disable sharing some of their personal information.
That setting is still there but you have no control over "mobile app advertising measurements", unless you are in Europe or in the UK where you can still opt out from sharing "non-public" personal information like device identifiers.
Twitter said in a statement that the move is "part of our ongoing work around transparency and control".
"Twitter shares certain non-public personal information with certain digital advertising platforms to help measure and optimize the effectiveness of our efforts to market Twitter on those platforms," said the company.
This information can include IP address and mobile device advertising identifiers for devices that open or log in to Twitter's mobile apps, but does not include your name, email, phone number, or Twitter username, said the company.
Twitter shares certain non-public personal information with advertisers who run mobile application advertising campaigns through its platform.
This information can include which ads a particular browser or device saw, watched, or otherwise interacted with.
Additionally, Twitter said it will now run ads for its app on Facebook and Google.
Users can opt out of sharing "non-public" data — such as whether or not they installed Twitter's app as a result of an ad — with Google and Facebook.