T-Mobile's new advertising business offers a way for marketers to gain insight into your app-using habits.

Ad Exchanger reports that App Insights is the new Un-carrier program and has been in beta for a year.

T-Mobile's program allows third-party marketers to purchase customer data from T-Mobile. It focuses on a key piece of information. It has exclusive access to which apps you use.

Anonymization of customer data is used. It's then pooled with similar interests and behaviour so that companies cannot buy an individual user's app history.

Still, it's creepy. This offering is promoted loudly on the company's website by its advertising segment, which boasts the phrase "Apps speak more loudly than words" across the top.

It invites potential clients to "leverage app insights, the strongest indicator for consumer intent." You can choose to opt-out.

T-Mobile has an Android and iOS app called Magenta Marketing Platform Choices. This allows you to see what companies have your data and even opt out completely.

App Choices can be used if you do not want to. Download a TMobile app to opt out of T-Mobile's app tracking.

Ad Exchanger states that iOS users can be excluded from the program, even if they have opted into app tracking.

This creepy behaviour by carriers is not new and will continue to be.

However, marketers are now looking for new ways to spy on their online activities, with companies such as Apple and Google allowing users to opt-out of tracking easier.

T-Mobile is the latest wireless carrier to offer this information.