Last update: $Date: 2003/11/08 16:33:10 $ UTC
In theory software becomes part of the public domain when it is released explicitly to the public domain, or when it falls out of copyright. Currently copyright in Canada lasts for fifty years after the author's death. Given the speed at which software changes, both the sale-value and the use-value of software will be long gone before the term of copyright expires. This effectively means that no software will enter the public domain unless the author explicitly releases it to the public domain.
Using public domain as a center point, we will try to create a one-dimensional line where the positive direction involves more obligations to share and the negative direction involves more obligations not to share.
It needs to be recognized that this is a considerable simplification of software licensing given that some license agreements can be very complex, and software may be licensed under more than one license agreement at the same time. While FLOSS tends to have large numbers of software packages sharing identical licenses, proprietary software tends to have different licenses for different version of the same piece of software, or for different customers.
source non-Copyleft Copyleft under typical Freeware Public Free Free NDA proprietary Shareware Domain Software Software +-------+------------+-+---------+---------------+-------------+ - 0 +Note: The GNU General Public License is the most popular Copyleft Free Software license. The Another diagram can be seen with FSF's Categories of Free and Non-Free Software page. The FSF also provides a Various Licenses and Comments about Them page.
The Microsoft Shared Source Initiative is an initiative which in their words "is a source licensing framework that makes source code broadly available while preserving the intellectual property rights". Shared Source is not defined in simple terms by Microsoft, and includes many different licensing models which seem to not share much in common to warrant a similar sounding name.
A document authored by the Open Source Initiative called Shared Source: A Dangerous Virus. According to that document "as of November 2002, Microsoft's Shared Source program offering is actually a collection of eight different programs with different restrictions".
The most controvercial feature of the Shared Source Initiative is the inclusion in some of the programs of a non-disclosure agreement (NDA). In the eyes of a software developer who is wanting to share their talents in a variety of situations, including both non-Microsoft proprietary software and FLOSS projects, it is suggested that the NDA may 'taint' a software developer or company that signs the NDA from working on other similar non-Microsoft projects. For these developers it is considered legally safer for them to simply not see the Shared Source Initiative code in the first place. It is from this perspective the Shared Source Initiative is considered to have more obligations restricting information sharing than typical proprietary software.
In most cases there is not a Non-disclosure agreement convering any information learned during the running of the software. An experienced user of an application can use their experience to train others in how to use that application without needing to worry about any legal limits.
It is important not to confused Shareware of Freeware with Free Software, as Shareware and Freeware do not adhere to the freedoms required by the Free Software and Open Source definitions.
The term Free Software is defined by the Free Software Foundation (FSF). The very related term Open Source is defined by the Open Source Initiative (OSI).