A method and system for enabling user interaction with computer software running in a computer system. The user is provided with an interface surface containing information relating to the computer software and including coded data indicative of at least one interactive element relating to the computer software. A sensing device in the form of an optically sensing stylus contains identifying data indicative of an identity of the user. When the user writes with the stylus, or uses it as a pointer, an operative end of the stylus is brought into contact with the interface surface. The sensing device senses indicating data indicative of the at least one interactive element using at least some of the coded data. The computer system receives the identifying data and the indicating data from the sensing device. The interactive element is identified in the computer system using the indicating data, and user data is identified using the identifying data. The computer software is operated at least partly in reliance on the user data, and in accordance with instructions associated with the at least one interactive element.