Open source licence proliferation has long been recognised to be a problem. The Open Source Iniatitives License Proliferation Committee wrote the following in May 2006:
- too many different licenses makes it difficult for licensors to choose
Some people use “license proliferation” to mean that there are just too many licenses and that someone needs to take steps to reduce the number. While this would be great, the OSI cannot make anyone use or not use a particular license. All we can do is educate and urge people to use a smaller subset of licenses. This comment generally came from individuals and small companies.
- some licenses do not play well together
Some people use “license proliferation” to refer to the fact that some open source licenses do not inter-operate well with other open source licenses. While we can urge people not to mix non-mixable licenses, we cannot keep people from doing so. This comment generally came from larger companies.
- too many licenses makes it difficult to understand what you are agreeing to in a multi-license distribution
This is related to the previous comment, but is somewhat different since it doesn’t complain about how the licenses interact, just that there are too many different individual licenses covering certain distributions and that it takes a lot of time to read and understand them all. This comment usually came from larger companies.
The OSI has, since the publication of this report, grouped licences as either “popular and widely used”, “special purpose”, “redundant”, “non-reusable”, “superseded” or “other”. OSS Watch encourage everyone to use one of the “popular and widely used” licences as these cover the major needs of most community and business models (the special purpose licences do have their place, but they are minority licences).
Today it was announced that the number of licences in the recommended group has been reduced from nine to eight since the Eclipse Foundation, along with IBM, have taken the steps necessary to supersede the Common Public License 1.0 (CPL) with the Eclipse Public License 1.0 (EPL).