Can be plugin used for our own applicatons?

[toplisek]

I have seen many Wordpress plugins. Issue is that they are perfect for other implementations and easy. Where is limit to take such plugins and use on other websites?

1. Is it UNlimited use with copyright notice or
2. wordpress plugin is prohibited to be placed into another application?
3. Where is limit of modification as plugin need to be modified in any way to suite my own application.

[rogerd]

I'm not sure I understand the question, toplisek, but a plugin should be like any other code you write, i.e., it can be protected by copyright and you can control its distribution.

Of course, that doesn't mean that others can't violate your copyright by unauthorized distribution, copying some or all of the code, etc. The burden is on you to police such activity, and your legal remedies may be too expensive to justify using them.

[tangor]

If you are the creator, then you can specify it's use copyright, copyleft, or the ability to copy and distribute, or require a license, or operate under GPL, BSD or other. If you are afraid to allow such use, don't release it. If you are asking about you using another's plug-in for a different purpose than originally intended, you'll need to ask that Creator if it is permissible.

If there's money involved you are urged to contact an attorney (and even if there's no money but a question of copyright or license might be involved)!

[toplisek]

I will be specific.
Check this copyright:
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/

--------------------

and quoted:
[gnu.org...]

1. The GNU General Public License is a free, copyleft license for software and other kinds of works.

2. When we speak of free software, we are referring to freedom, not price.

3. ...that you can change the software or use pieces of it in new free programs, and that you know you can do these things.

4. Therefore, you have certain responsibilities if you distribute copies of the software, or if you modify it: responsibilities to respect the freedom of others.

Last one is issue as I understand...

[tangor]

Copyleft applies only when a person seeks to redistribute the program. One is allowed to make private modified versions, without any obligation to divulge the modifications as long as the modified software is not distributed to anyone else. Note that the copyleft applies only to the software and not to its output (unless that output is itself a derivative work of the program[34]). For example, a public web portal running a modified derivative of a GPL'ed content management system is not required to distribute its changes to the underlying software because its output is not a derivative.
[edit] Licensing and contractual issues

The GPL was designed as a license, rather than a contract. In some Common Law jurisdictions, the legal distinction between a license and a contract is an important one: contracts are enforceable by contract law, whereas licenses are enforced under copyright law. However, this distinction is not useful in the many jurisdictions where there are no differences between contracts and licenses, such as Civil Law systems.

Those who do not accept the GPL's terms and conditions do not have permission, under copyright law, to copy or distribute GPL licensed software or derivative works. However, if they do not redistribute the GPL'd program, they may still use the software within their organization however they like, and works (including programs) constructed by the use of the program are not required to be covered by this license.

[en.wikipedia.org...]
This language is a bit less dense. You still haven't revealed: Is this for YOUR OWN USE at YOUR OWN WEBSITE under the terms of GPL or do you intend to modify the source code then copy/redistribute it?

[toplisek]

No way to redistribute. I'm seeking way to modify code for my own projects.

What is actually definition of REdistribution? If I understand projects for clients is REdistribution even you just modify or copy some sort of code.

Can be this avoided by placement of copyright source if you use as developer for your clients?

[tangor]

We can't give legal advice and---though opinions abound---you are urged to consult an attorney before action is taken.

It sounds like you are modifying code to distribute (sell?) to clients. You'll want a lawyer to take a look at your intent and the limits of the GPL associated with the plug-in you want to modify. Under GPL one can make mods and use the software ON YOUR SITE with no problem. Put that modified code on other systems not yours and/if charge for that without the GPL and you certainly could be in violation.

[toplisek]

As I have to develop new wordpress plugin this can happen very fast if this plugin is modified. This is the reason why I posted issue with modification. I have no intentions to sell plugins but posted opposite case.

So, in your opinion there is not simple answer for modification if somebody redistribute to their clients for money as there is also limit inside each GPL.

Inside each plugin I have to set also additional terms (limits) regarding modification. Is this correct?

[tangor]

IANAL, but you are asking legal questions. So, best that can be offered is an opinion.

In short, you're using someone else's copyrighted work under GPL for YOURSELF. No problems. All done. Let's get THAT part settled first. Yes or no?

If for someone ELSE and you are paid to do it, a different result, and could/will infringe scope of GPL if notifications of mod and full copyright credit to original Creator is not included.

If your modified plug is redistributed by others without full copyright disclosure per GPL, then again, an infringement (more so)

Best bet is to contact the Creator of the plugin you wish to modify, work with them, and jointly release. They might find your mods beneficial!

That's what I would do. Any reason why you can't?