Many form contracts are only included in digital form and are presented to a user only as a click-through that the user must „accept.“ Since the user may only see the agreement after the purchase of the software, these documents may be liability contracts. A common criticism of end-user licensing contracts is that they are often far too long for users to spend time reading them carefully. In March 2012, the PayPal end-user license agreement was 36,275 words and in May 2011, the iTunes agreement was 56 pages long.  The sources of information that reported these results stated that the vast majority of users do not read the documents because of their length. Software companies often enter into specific agreements with large companies and public authorities, which include specially designed support contracts and guarantees. Export Control U.S. export laws and regulations and all other relevant local export laws and regulations apply to programs. You agree that such export control laws govern your use of programs (including technical data) and all services provided under this agreement, and you agree to comply with all of these export laws and rules (including „as an export“ and „as a re-export“). They accept that no data, information, program and/or material from programs or services (or direct products of these services) is exported or used for purposes prohibited by these laws, including, but not exclusively, the proliferation of nuclear, chemical or biological weapons or the development of missile technologies. As a result, you confirm that a free software license grants users of this software the rights to use for any purpose, modify and disseminate creative works and software, both of which are prohibited by copyright rules and are generally not granted with proprietary software. These licenses usually contain a disclaimer, but this feature is not just for free software.
 Copyleft licenses also contain a key add-on clause, which must be followed to copy or modify the software, requiring the user to provide source code to the factory and distribute its changes under the same license (or sometimes compatible); effectively to protect derivative works from the loss of original permissions used in proprietary programs. Unlike THE EULAs, free software licenses do not function as contractual extensions of existing legislation. No agreement is ever reached between the parties, because a copyright license is merely a declaration of authorization for what would otherwise not be permitted by default under copyright.  Click-Wrap Licensing Agreements cover the formation of website-based contracts (see iLan Systems, Inc. v. Netscout Service Level Corp.). A common example occurs when a user has to accept a website`s licensing terms by clicking „Yes“ in a pop-up to access the website`s features.