----- Original Message -----
From: "Dan Collins" dcollin1@stevens.edu
On Fri, Dec 30, 2011 at 9:15 AM, Jay Ashworth jra@baylink.com wrote:
----- Original Message -----
From: "Tim Starling" tstarling@wikimedia.org
On 30/12/11 08:30, Dan Collins wrote:
On Thu, Dec 29, 2011 at 4:24 PM, Huib Laurens sterkebak@gmail.com wrote:
It doesn't need to be compatible or open-source right?
GPL 2.0 section 2 b:
b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
You can modify GPL software for private use. That clause only kicks in when you "distribute or publish" the work, so you're generally OK if you're just using it within a single company. Maybe that's what Huib meant by "closed source".
And since we're not under the *Affero* GPL, you can modify it, *and make it publicly available*, and still not be constrained by the licence (I don't think I've got that backwards, do I?)
You may be slightly confused or I may be slightly not a lawyer, but:
The Affero licence states that you may not use, distribute, or publish any licensed or derivative work under any other licence. The vanilla GPL states that you may not distribute or publish licensed or derivative work under any other licence.
It is therefore acceptable for Big Business Inc. to modify MediaWiki and **use** it as bigbusiness.com, however they may not sell or give (**distribute**) their modified version to any other company or individual unless they obey the terms of the License. So if whoever it is decided to modify MediaWiki by adding a closed-source extension, however that works, and then gave that to their customers to put on their websites, then they have violated the GPL, because they must make available the complete source of their **derivative work** which they have **distributed**. If however they have decided to modify MediaWiki by adding a closed-source extension, however that works, and then placed that on their servers at the request of a customer, then they have not violated the GPL because their derivative work is being **used** but not distributed.
This sort of thing gets complicated when you think about things like paid hosting - you're selling it and making it available for use but not distributing it. You'd think that they're breaking some provision by making money off of their modified MediaWiki but I'm pretty sure they aren't as long as the derivative work stays on their servers. (but is the HTML generated then also a derivative work? probably not?)
Ok, ok, I'll go look. :-)
Yeah, I was right.
That's what the AGPL does: it makes it a violation of license to make non- public changes to a GPLd app, *and then make it available as a webservice, without physically distributing the code*.
The GPL proper does not prevent that, which is the topic we're discussing here: since the MediaWiki code is not under AGPL, you can modify it, not release your mods, *and run it on your own web service*, and not violate the license.
If you distribute it outside your organization in such a fashion, though, *that* trips the traditional GPL.
Cheers, -- jra