Yes, I know this is a sideline of this discussion, but I simply cannot let this statement stand:
If you absolutely want to have credit, you should probably simply display a copyright notice ( (c) Mad4Joomla - 2012) on the frontend of your extension(s).
Removing that copyright notice would be a direct violation of GPL, so users would not be allowed to do it. JED would probably also have a hard time adding a rule that directly opposes a GPL license provision.
Just to clarify: If we're talking about the default GPL, the bold statement is false
. Leaving aside the exception noted below (which only concerns distribution of copies), you are free to remove any such notices from the output of a program that is licensed GPL - of any version. If those exceptions are exercised, the bold statement is only half true.
The rule of thumb is: changing the output of a piece of software is precisely the kind of right that the GPL protects.
To quote the GPL
You may convey verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice; keep intact all notices stating that this License and any non-permissive terms added in accord with section 7 apply to the code; keep intact all notices of the absence of any warranty; and give all recipients a copy of this License along with the Program.
Using the software to produce an output does not constitute conveying a copy of the software:
To “convey” a work means any kind of propagation that enables other parties to make or receive copies. Mere interaction with a user through a computer network, with no transfer of a copy, is not conveying.
Furthermore, even distributing copies of the software with the interface notice of copyright removed is legal and perfectly fine - as long as the source code (remember - this is the thing that the license actually covers) still keeps its notices:
An interactive user interface displays “Appropriate Legal Notices” to the extent that it includes a convenient and prominently visible feature that (1) displays an appropriate copyright notice, and (2) tells the user that there is no warranty for the work (except to the extent that warranties are provided), that licensees may convey the work under this License, and how to view a copy of this License. If the interface presents a list of user commands or options, such as a menu, a prominent item in the list meets this criterion.
In that regard, the pure claim of copyright does not satisfy the conditions for an "Appropriate Legal Notice" and are thus not eligible for the kind of protection noted.
What you may do, however, is add special terms, as noted in GPLv3 Section 7:
Notwithstanding any other provision of this License, for material you add to a covered work, you may (if authorized by the copyright holders of that material) supplement the terms of this License with terms:
b) Requiring preservation of specified reasonable legal notices or author attributions in that material or in the Appropriate Legal Notices displayed by works containing it; or
c) Prohibiting misrepresentation of the origin of that material, or requiring that modified versions of such material be marked in reasonable ways as different from the original version; or
Furthermore, the GPL only allows for amendments as noted in Section 7, otherwise:
All other non-permissive additional terms are considered “further restrictions” within the meaning of section 10. If the Program as you received it, or any part of it, contains a notice stating that it is governed by this License along with a term that is a further restriction, you may remove that term.TL;DR:
The GPL is only a concern here if we're talking about distributing copies
. If we are
talking about distributing copies, additional permissions or restrictions may
My personal opinion: I would recommend staying away from any developer who, through whatever means, forces or tries to force his or her users to display copyright notices. It is vain and unnecessary.
Developer of the AEC Membership Management Component: http://valanx.org
Fellow of the Free Software Foundation Europe (and so can you: http://www.fsfe.org