IMPORTANT UPDATE: The only meaning of this post is to raise a critical point of view about the OSL license (choosen by Magento), absolutely not to discourage someone from using Magento itself, I simply love it.
The license is really difficult to read if you’re not an English expert, anyway let’s take a look at what GNU says about OSL (bold by me):
The Open Software License is a free software license. It is incompatible with the GNU GPL in several ways.
Recent versions of the Open Software License have a term which requires distributors to try to obtain explicit assent to the license. This means that distributing OSL software on ordinary FTP sites, sending patches to ordinary mailing lists, or storing the software in an ordinary version control system, is arguably a violation of the license and would subject you to possible termination of the license. Thus, the Open Software License makes it very difficult to develop software using the ordinary tools of free software development. For this reason, and because it is incompatible with the GPL, we recommend that no version of the OSL be used for any software.
We urge you not to use the Open Software License for software you write. However, there is no reason to avoid running programs that have been released under this license.
Being incompatible with GPL it’s a big issue, it avoids avery integration between Magento and any GPL software and it’s a big limitation.
A normal day of a free software developer:
I write a patch for Magento. That patch is released under OSL becuase that’s what OSL impose. I send the patch to some public mailing list or post it to a forum because I want to help developers creating a better and bug-free software.
In this situation I’m violating the license and I’m loosing my right to use the software anymore. I think this is a serious trouble that should be avoided and solved.
A note from OSL wikipedia page:
the OSL has never been tested in court and is not widely used
In fact we can see that only 3 project are listed (in that wikipedia’s page) to be using OSL.
In a forum post Roy Rubin (CEO of Varien, creators of Magento), says that a big difference from GPL is that OSL defines distribution over a network as a distribution. If this is the most important aspect Varien is taking care of, than I suggest to switch to Affero GPL 3, which is completely compatible with GPL 3 and takes care of the network distribution of a GPL software.
We all know that many people do not pay serious attention to all the license implications, but all the others could stop using Magento because of all the problems above and I don’t think this is a good thing for the project.
UPDATE: AGPL3 would not be suitable for the frontend, the license switch proposal is just a provocation.