An apparatus for capturing and storing a co-marketer identification symbol representing an identity of an entity that has referred a user on a user station to a computer service, wherein the user station is coupled to the computer service by a communications path. A database is provided for storing a plurality of user records. Each of the user records includes a user identification field for storing information uniquely associating each of the user records with a user, and a co-marketer identification field for storing identity information representing the identity of an entity that directed the user to the computer service. An enrollment means is coupled to the communications path and the database, and is provided for enrolling a user on the computer service. The enrollment means includes means for determining a co-marketer that directed the user to the computer service, and means for assigning a unique user identification number to the user. The enrollment means further includes means for storing a co-marketer identification symbol representative of a co-marketer and the unique user identification number of a user in the co-marketer identification and user identification fields, respectively, of one of the user records.