Assuming one accepts the premise that copyright laws are still important to ensure the advancement of knowledge through journals and other means of distribution, it is the licensing issues (i.e, the application of statutory commercial contract law governing the relationships of particular parties to particular contracts, as opposed to the statutory law principles promulgated in respect of the relations between the producers and the users of copyrighted works generally) that may fast be becoming the most important legal overlay to the digital library environment, more important even than changes in copyright law.  Although copyright law  and limitations imposed contractually through licensing both often share a common goal of protecting intellectual property, there are important distinctions in how  these two legal constructs go about accomplishing their respective purposes, with which distinctions librarians must become increasing familiar.  Ann Okerson sums up these differences cogently:
	“Copyright represents a set of general regulations negotiated through statutory enactment.  The same laws and guidelines apply to everyone in the country.  Licenses, or contracts, on the other hand, represent a market-driven approach to such regulation.  Each license is arranged between a willing purveyor and a willing licensee, resource by resource.  The owner of a piece of property is free to ask whatever price and set whatever conditions the market will bear.  Source: Ann Okerson , "Copyright or Contract?" Library Journal 122 (September 1, 1997) p. 137.