The invention deals with a method of constructing a database (100) of users of mobile telecommunication terminals. It comprises the following steps: - first user data are transmitted by means of a first program of an email intended for the user; - first terminal data (23) are transmitted, the terminal data (23) forming a first set (23); - each first user datum (22) is associated with the first set (23); - second user data (71) are transmitted by means of a second program of an application consulted by the user; - second terminal data (23) are transmitted, the terminal data (23) forming a second set (23); - each second user datum (71) is associated with the second set (72); - a comparator (98) compares the first and second sets (23, 72).
