A user data annotation method in a system comprising a first terminal, a second terminal, a third terminal and a server, comprising: 1.1 receiving, by the server, location information of a first user corresponding to the first terminal device, behavior information of the first user, and sensor data of each sensor on the first terminal device, which are sent by the first terminal device in a process of a game, wherein the behavior information of the first user is information representative of an ongoing action of the first user; 1.2 annotating, by the server, the location information of the first user, the behavior information of the first user, and the sensor data to obtain annotation data of the first user; and wherein after the receiving, by the server, location information of the first user corresponding to the first terminal device, behavior information of the first user, and sensor data of each sensor on the first terminal device, which are sent by the first terminal device in a process of a game, the method comprises: 1.3 receiving, by the server, identifier information of the second terminal device invited to the game, which is sent by the first terminal device in the process of the game; 1.4 sending, by the server, an invitation notification message to the second terminal device according to the identifier information of the second terminal device to notify the second terminal device of joining the game, and sending the location information of the first user to the second terminal device, whereby a third user corresponding to the third terminal device that chooses to join the game in the second terminal guesses a behavior of the first user and gives guessed behavior information according to the location of the first user provided by the server, the current time and particulars of the first user; and 1.5 receiving, by the server, guessed behavior information sent by the third terminal device, comparing the behavior information of the first user with the guessed behavior information, and 1.6 sending a comparison result to the third terminal device so that the third user knows a guess result. 1.1 receiving, by the server, location information of a first user corresponding to the first terminal device, behavior information of the first user, and sensor data of each sensor on the first terminal device, which are sent by the first terminal device in a process of a game, wherein the behavior information of the first user is information representative of an ongoing action of the first user; 1.2 annotating, by the server, the location information of the first user, the behavior information of the first user, and the sensor data to obtain annotation data of the first user; and 1.3 receiving, by the server, identifier information of the second terminal device invited to the game, which is sent by the first terminal device in the process of the game; 1.4 sending, by the server, an invitation notification message to the second terminal device according to the identifier information of the second terminal device to notify the second terminal device of joining the game, and sending the location information of the first user to the second terminal device, whereby a third user corresponding to the third terminal device that chooses to join the game in the second terminal guesses a behavior of the first user and gives guessed behavior information according to the location of the first user provided by the server, the current time and particulars of the first user; and 1.5 receiving, by the server, guessed behavior information sent by the third terminal device, comparing the behavior information of the first user with the guessed behavior information, and 1.6 sending a comparison result to the third terminal device so that the third user knows a guess result.