Dave Burke makes the interesting claim that Community Server is an open source application. Whether this is true or not of course depends on your definition of the term Open Source. Here is Dave’s definition.
To talk about Community Server and Open Source we should start with a baseline definition of an Open Source application: All of the source code is available. For free.
But is that all there is to Open Source, access to the code? Is mere access to the code the fairy dust that has inspired such a passionate movement in the software community?
Certainly the term Open Source has had a history of ambiguity, so that definition might contain some validity. But I do not think that is the commonly agreed upon minimal criteria for something to be considered Open Source.
Open source isn’t just about whether the source code is available, it is all about the license to the source code.
My favorite definition of open source software is The Open Source Definition (or OSD for short) on the Open Source Initiative website.
The definition starts with the following introduction and then lists serveral criteria for open source software.
Open source doesn’t just mean access to the source code. The distribution terms of open-source software must comply with the following criteria:
The first criteria listed is Free Redistribution which states...
The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.
Contrast this to the Community Server license agreement 2.0 which states...
3g. Distribution. You may not distribute this product, or any portion thereof, or any derived work thereof, to anyone outside your organization. You are not allowed to combine or distribute the Software with other software that is licensed under terms that seek to require that the Software (or any intellectual propertyin it) be provided in source code form, licensed to others to allow the creation or distribution of derivative works, or distributed without charge.
For many people, the terms of the Community Server license might not be a problem. They are not terribly restrictive. If you plan to use Community Server under the community license your only requirement is to display the Powered By Community Server logo on every page of the site that uses Community Server.
However for many others, these terms are restrictive enough. For example, suppose you don’t like the way development is progressing on Community Server. You cannot fork the code base and start a new project based on the source code. Although a fork may seem like a bad thing, Karl Fogel points out in his book "Producing Open Source Software - How to Run a Successful Free Software Project that the threat of a fork is what keeps the leader(s) of an open source project from being tyrannical. It is this threat of a fork that motivates and requires open source projects to be well run.
Not every open source license is created equal as I pointed out in my guide to Open Source Software Licensing. For example, under the BSD license in which Subtext is licensed, you and I are free to create a commercial derivative version of Subtext and keep your changes to the code closed source and proprietary. That’s right. If you wanted to (and had the ability to), you could package up the Subtext source code in its entirety and start selling it as a packaged product.
Note that you can’t turn around and claim that you have the copyright to the Subtext code. You would only have copyright to your changes to the code. Pretty much the only restriction is that the original license must be retained with with the code, but it does not have to be publicly visible in your site (such as in an about box).
In contrast, with a GPL Licensed project, you could start selling it, but you couldn’t keep your changes closed source without violating the terms of the license.
In the end, I think we need to agree on a term for unique products such as Community Server in which the source code is freely available, but does not fit the definition of an open source product. I suggest the term Source Available.
Please do not misconstrue this as an attack on Community Server or its licensing. I have met both Scott Watermasysk and Rob Howard and they are both very smart and capable leaders of a strong company. Community Server is a great product and deserves the recognition it gets. I am not a zealot and have no beef with closed source products. Certainly my livelihood depends on many such products.
At the same time, I am passionate about Open Source software and it is important to me to help keep the distinctions clear and educate others on what open source software is and the value it provides.