If you use Twitter on your cellphone, the social media site will soon begin tracking which apps you use unless you actively opt out.
The purpose is to offer targeted advertising,
Recode reports.
Twitter is able to know some things about its users based on the content of their tweets and whom they follow, but the ability to know what apps they use would provide more data.
Twitter will not, however, be looking at the content of those apps, Recode reports. For instance, Twitter would be able to know if a user had downloaded Spotify, the music-listening app, but not which songs were listened to or how often the app was actually used.
The update was made to Apple iOS phones on Wednesday and will be added to Android phones soon.
The move is also aimed at luring new users to Twitter. Currently, new users don't see a varied timeline until they have built up a list of people to follow. In recent months, Twitter has been showing people tweets from people they don't follow but who are similar to others that they do, and checking which apps they use is expected to aid in that process.
Apple's iOS and Google's Android systems both already allow developers to see which apps people are using, but it is allowed only if it is disclosed in the user agreement.
Facebook also collects information on which apps its users have installed, but does so only for apps that use its own developer kit, such as Candy Crush, Recode reported.
Since Twitter is using an opt-out for the update, users will automatically be opted in unless they change their settings to opt out. Users who already have opted out for interest-based ads will not have to opt out again.
Twitter details how to opt out on
its support page.