1. A method of distributing software comprising: providing the software to an entity, said entity having a right to install an instance of the software on each of one or more machines; providing to each of the one or more machines a license that permits a first mode of usage of an installed instance of the software if there is a certificate, issued by a license server associated with said entity, that is present on a one of said machines on which said installed instance of the software is running; authorizing said entity to issue one or more certificates that are acceptable under terms of said license to permit usage of the software, said certificate being one of said certificates.