Especially in the software area there is a special type of license besides the usual purchasable licenses (new and used software) which enables a comprehensive and almost completely free-of-charge use of the respective software or even the source codes. The areas of application, for which open source software is meanwhile available, are very broad and involve operating systems via office applications and e-mail programs as well as web-based content-management-systems.
These so-called Open Source Software Licenses are extremely popular with developers, programmers, web designers and administrators. Nevertheless it has to be observed that open source licenses are subject to different far reaching rights.
The GPL demands that the program has to include a comprehensible source code when passed on apart from the in technical terms called binary and that changed versions also have to be in accordance with the GPL agreement, if one does not want to risk losing the product rights.