The advertising program will start and policy changes will take effect on February 26, 2021. For contractors registered in this program, data such as URLs and types of websites visited, and applications used were collected. T-Mobile explains that this data is anonymized and provided to the advertising identifier and other identifiers.
T-Mobile said that it is based on this setting as many people know that they prefer more relevant advertisements. This change allows contractors to display advertisements tailored to their interests.
U.S. law has restrictions on telecommunications companies regarding the handling of customer’s own information, such as call records and payment information, but there are almost no restrictions on the handling of mass user data created by using smartphones. It is pointed out that Verizon, the No. 1 market share operator in the US, and AT&T, the third-largest, are also collecting user data in a form close to T-Mobile. Related information can be found here.