In regard to the amount and substantiality of the portion used, a court will most probably conclude that if an entire work is reproduced, that reproduction is an unfair use of the original author's work. However, this factor, as compared to the first and fourth factors, seems to be less important in the balancing equation which leads to a finding of infringement. The effect of the use is the most important of the four fair use issues. A key aspect of this factor is that a work is considered an infringement if it displaces not only the current market, but also, a potential market. The issue of the effect on the potential market in large part goes to the author's exclusive right to prepare derivative works.
Derivative works are works that have altered the original copy in some way.
In a world where you do not have to sign your name on a card to borrow a book or break the plastic off a cassette disk to listen to the music, the only way an artist is going to get compensated is if there is an established method of licensing and tracking. While of course, any proposed licensing scheme will not be absolutely accurate, it is more reliable than any other possible method to accurately reflect the use of a protected work. Moreover, when the vehicle upon which all of this activity will be conducted has the greatest surveillance capacity to date, and the least chance of human error, it is probable that the artist will be more systematically compensated for the uses of their works, then they have been in the past, or will be when compared with current Superhighway infringing events. Fair use does not always mean that people use the work for free, it means more appropriately that if they do use the work, they are not subject to be sued for that use. Fair use is really a privilege in people other than the artist or copyright owner to use the copyrighted material in a reasonable manner, without getting the consent of the owner.