The use of contract law as an aid to copyright law in the digital world can erode the very foundations of intellectual property, that is, to reward authors for their creations and further stimulate creative activity in others for the public benefit. When George Washington asked the United States Congress to enact copyright legislation in 1790, he argued that such legislation would increase the national stock of knowledge, and observed that knowledge is “the surest basis of public happiness”.
Contract law not copyright law aids copyright owners to protect digital versions of their work. Digital works can be sold subject to contractual terms that restrict the ways in which they can be used. Contract between publisher or owner and purchaser can limit the numbers of people who are allowed to have access to them, the sorts of people who are allowed to have access and the permitted purposes of access.
Lessig says the lesson in the future will be that copyright is protected far too well. The problem will center not on copy-right but on copy-duty – the duty of owners of protected property to make that property accessible.
Not only can publishers determine how much of their works can be copied, and for what purposes, they can also decide whether or not their works could even be accessed. But of course, contract cannot deliver complete protection to copyright owners in a digital world. The doctrine of privity of contract confines its reach, and copyright still has a role to play in protecting works.
 McLean, Ross and Flahvin, Anne. The Digital Agenda Act: how the new copyright law (and contract) is redefining the relationship between users and owners of copyright. op cit
 Lessig, Lawrence Code and other laws of cyberspace op cit p. 127