You can't sell Drupal, or any modification you made to Drupal. You can charge money for having to make these changes but you can't make these changes available under a commercial license. Why not? Because Drupal's license, the General Public License 2 (GPL 2), mandates that all modifications also be distributed under the GPL.

But when you are providing a service through the web using GPL'ed software like Drupal, you are not actually distributing the software. You are providing access to the software. Thus, a way to make money with Drupal is to sell access to a web service built on top of Drupal. This is commonly referred to as the web services loophole.

Some people say this loophole is inconsistent with the values of the Free Software movement. Others think of this loophole as an interesting feature. I'm in the latter camp. In fact, I predict that 2007 will bring a small tsunami of Drupal distributions built around a hosted service model.

Fact is, when the GPL was created 15 years ago, it did not really predict a world of web services. Version 3 of the GPL, expected to be released in 2007, will tackle this issue. It will allow developers to add an optional clause to the license that requires hosted service providers to share the source code and their modifications. This optional clause can be found in section 7.b.4 of the most recent draft of the GPL 3 (subject to change):

Additional requirements are terms that further constrain use, modification or propagation of covered works. This License affects only the procedure for enforcing additional requirements, and does not assert that they can be successfully enforced by the copyright holder. Only these kinds of additional requirements are allowed by this License: ... snip ... 4) terms that require, if a modified version of the material they cover is a work intended to interact with users through a computer network, that those users be able to obtain copies of the Corresponding Source of the work through the same network session.

Personally, I don't see us adding such a clause to Drupal. It doesn't bode well with the way people use Drupal, or any content management system for that matter. Here is just one example: most people theme their sites by downloading and modifying one of the available GPL themes. If we were to add the additional clause, this would no longer be desirable, because you'd be forced to share all your modifications, including your theme's. It is problematic when you want to create a unique site or brand.

So long live the web services loophole!


bertboerland (not verified):

I agree on being very restrictive when it comes to changing the license under which the Drupal products are distributed right now, and that delivering Drupal as a service doesn't mean you have to share (as in Open Source) the elements that make this service.

While we are at the sensitive subject of Open Source licensing, can you imagine ever using section 4 of the GPL for banning "bad vendors" distributing Drupal like nmap did with SCO? For example, if Suse would include Drupal -- I don't think they do -- punishing Novell?

greggles (not verified):

It is great to hear your stance on the subject so everyone knows what you believe (and therefore the view for Drupal project). Personally, I agree with your point of view and am glad to hear that this is the direction of the Drupal project.

jakeg (not verified):

It is a fantastic 'loophole' (though I don't really consider it that) and one which I strongly suggest remains for Drupal, else I would have to change to a different system.

Steven (not verified):

Linus Torvalds doesn't like the GPL3 draft either; see this link for more info on his views; and another take on it by kernel developers can be found here.

The problem is that the GPL is overstepping its boundaries as a software licence. IMHO becoming too fundamentalistic.

Pete Prodoehl (not verified):

"You can't sell Drupal, or any modification you made to Drupal." The GPL does say "You may charge a fee for the physical act of transferring a copy..." and "you have the freedom to distribute copies of free software (and charge for this service if you wish)"

So I could "charge" you for a CD containing a copy of Drupal, but you would be paying for the media, and/or the time it takes to produce the CD, but not the software itself. The second part seems to suggest you could charge for downloads as well, which makes sense because bandwidth isn't free.

Besides all that, I agree that the loophole is a good thing. It allows people to build commercial services on top of open-source software. I just hope that the creators and the projects can benefit from this.

Ber Kessels (not verified):

So I could "charge" you for a CD containing a copy of Drupal, but you would be paying for the media, and/or the time it takes to produce the CD, but not the software itself. The second part seems to suggest you could charge for downloads as well, which makes sense because bandwidth isn't free.

Not entirely true. If I want, the GPL allows me to charge any amount I want for a Drupal tarball. I could even charge 1 million per copy if I wish. All I need to do is a) provide a copy of GPL with it (redistribute under GPL) and b) provide the source code.

So, in theory anyone can sell Drupal as is. It makes little sense to do so, because it is available for free too, and because anyone could re-distribute the copy he/she bought from me for free too, but nothing in the GPL says I cannot sell Drupal tarballs.

Anonymous (not verified):

Finally! Someone who understands the GPL! I concur 100%. You can charge as much as you want for GPL-licensed software, but since you can not restrict redistribution, and you have to provide the source code for no more than the cost of distribution, there is little incentive for anyone to pay for it. The "free" in free software means freedom of use, and has nothing to do with the price of software.

chx (not verified):

Zealotry was never good and certain people around GPL are known to be zealots. However, GPL v1 and v2 was created for another age and it provides enough loopholes so that it's still useful for non-zealot, real world usages. Now, GPL v3 changes adjusts the license so that it's usable only for zealots of this age. Ten years from now, GPL v3 will likely be usable for normal people through loopholes...


The copyright on Drupal's source code is distributed among hundreds of contributors. For such a license change to happen, every contributor would have to transfer his copyright to a central body, such as the Drupal Association. Then that central body can decide to change the license.

Anonymous (not verified):

Everyone seems to be on the same page here, just thought I'd chime in with a contribution.

The GPL explicitly states that you can charge for copies of the available for free software, and encourages it as profit generation trickles back into the community.

So in this there are no need for loopholes...


outinsun (not verified):

AFAIK GPL v2 does not actually define the term "distribution". I have long wondered about this precise issue. I tried asking the FSF about it but never got a response. Anyone have any thoughts as the precise meaning of "distribution"?