It means that the user allows Douyin to obtain the permission of the mobile phone address book and has added the corresponding contact as a friend. Douyin address book friends means that the user allows Douyin to obtain mobile phone address book permissions and has added the corresponding contacts as friends. In this way, users can easily find their friends in their address book and see their friends’ updates, likes, comments and other interactions on Douyin. In addition, Douyin will also recommend other unadded users based on the user's address book friends to expand the user's social circle.