it merely hinted at hidden terms that could not be evaluated by the customer until after purchase. Zeidenberg also claimed that by trying to prohibit its users from copying phone numbers from its database, ProCD was violating copyright law because phone numbers are facts, and facts cannot be copyrighted. The district court ruled that the buyer of a software package is not required to observe a shrinkwrap license because in this case, the message on the outside of the CD-ROM box (under the shrink wrap) only served as a notice that there was a contractual agreement inside, and did not constitute an enforceable contract in itself. Thus, the shrinkwrap was not a contract and Zeidenberg had not committed a violation. ProCD appealed this ruling to the United States Court of Appeals for the Seventh Circuit. Circuit court ruling The Seventh Circuit overturned the lower court decision and ruled that a shrinkwrap license is in fact an enforceable contract. The circuit court held that while the message on the outside of the CD-ROM package was merely a notification of the full contract to be found inside, this did not force a purchase as Zeidenberg claimed. Instead, ProCD invited buyers to return the package to the retailer if they could not accept the terms of the agreement: "If you do not agree to the terms of this License, promptly return all copies of the software, listings that may have been exported, the discs and the User Guide to the place where you obtained it." The circuit court also held that Zeidenberg then had ample opportunity to review the license after opening the package, and indicated his acceptance of the agreement by clicking the relevant field before he could begin using the SelectPhone software. On Zeidenberg's copyright argument, the circuit court noted the 1991 Supreme Court precedent Feist Publications v. Rural Telephone Service, in which it was found that the information within a telephone directory (individual phone numbers) were facts that could not be copyrighted. For Zeidenberg's argument, the circuit court assumed that a database collecting the contents of one or more telephone directory was equally a collection of facts that could not be copyrighted. Thus, Zeidenberg's copyright argument was valid. However, that did not lead to a victory for Zeidenberg, because the circuit court held that copyright law does not preempt contract law. Since ProCD had made the investments in its business