Computer-mediated learning products-whether they are guided practice exercises, tutorials, simulations, games, hypertext, multimedia and web documents merely carry out the directives (rules. programs, scripts. mark-ups) from a human tutor who originally designed the particular instructional or informational system and its subject matter. a computer system has no idea of the meanings of the messages (i. e., groups of "signs") being sent back and forth between the tutor and students. a computer system is a medium which conveys those human messages.