As a programmer, beside design and coding, you have to understand licensing at least to some degree. For a beginner, this is a vast and confusing topic.
You can write your own license. Simply tell, what you want with your software to be done by others, and what not. But a laymans writing might not hold legal stress, it might finally just not work as expected. Why? Licenses are written in the lawyer language, very elaborated.
A license must be obligatory, mandatory, compulsory, obliging, courteous, friendly!
There exist quite some ready-made proven licenses, you can choose one from. This is very recommended. But which one? Understanding the exact implications of a given license, is also no easy task. But much easier than writing an own license.
When constructing a license, the lighter part is to grant the end user her rights. This is solved pretty equally throughout the open source licenses. The harder part is, to formulate the rights of the other programmers: how exactly they may modify, embed, re-use or branch the sources. That is where the various open source licenses differe.
Below an incomplete overview, mainly open source and some proprietary.
The MIT License, or more precisely called X11, is one of the oldest and most simple licenses. It is so nice short and understandable. Read the fineprint here.
It is the most permissive license existing, there is no defense built in to protect the authors work. It is just a plain liability exclusion. It is applicable if you need no guard against any business flow off.
More information you find e.g. in Wikipedia under MIT_License.
The GNU project provides several licenses, with the GNU General Public License (GNU GPL) as the most popular free open license today. A fineprint of the GNU GPL 3.0 is here.
The complete GNU license family:
For more information see the projects homepage http://www.gnu.org.
A nice discussion of the implications having the GNU GPL mixed with other licenses is found on https://kb.askmonty.org/en/licensing-faq .
Read the fineprint here. A program running under the IBM Public license is e.g. Postfix.
The IBM Public License has eventually the interresting aspect to provide protection against branching the project.
More information and links you find e.g. in Wikipedia under IBM_Public_License
A nice short young open source license. The fineprint see here.
A program running under this license is e.g. Crack.NET (http://joshsmithonwpf.wordpress.com/cracknet ) .
(Todo - Find out the key concepts of the MSPL.)
This is a combined hybrid MIT / Creative Commons Licenses. It is based on MIT/X11 with some additions. It is pretty short anyway! The fineprint see here.
This license is interresting, because for Joes/V4/V4Net/V5, such might be a way to stick to the MIT/X11 license, and compensate for it's shortcomings at the same time.
A (or the) program running under this license is of course Paint.NET (http://www.getpaint.net ).
This is a set of open free licenses specialized for general creative work e.g. books, photos, films, everything. A fineprint of the Creative Commons Attribution see here.
Just saying, a work is under the Creative commons does mean nothing. You must tell which of them, each of them has a different meaning (see http://creativecommons.org/licenses). The Creative Commons licenses set is this:
And you know, never is licensing simple - there are even more flavours of the Creative Commons Licenses, e.g. specialized on german/austrian law (settled in Austria 2008).
The WTFPL - Do What The F*ck You Want To Public License is an extremely simple and permissive license. It is defined on sam.zoy.org/wtfpl .
Sample usage. E.g. it is attached to a code snippet in the Oxid eShop Forum, posting Beliebige Objekte im Smarty Template laden .
[Question: What exactly is the differences between the MIT/X11 and the WTFPL licenses?]
Apache License. This allows the software to be embedded in closed software.
The BSD License is a collective name for several distinct open source licenses, which differ in their amount of clauses. See e.g. http://de.wikipedia.org/wiki/BSD-Lizenz .
'Proprietary' closed licenses. One example is Borland's 'No-Nonsense License'. (Todo: Provide example of a closed source license.)
Python Software Foundation License. The PSFL allows the software to be modified and embedded into proprietary software. The PSFL is compatible with the GNU GPL (in one direction). That means, you can modify and embed Python in your proprietary project. But you must not embed GPL software into Python, since GPL prohibits it's software to go proprietary.
wxPython License. ...
A nice collection of licenses, each with a short summary, you find at http://www.codeproject.com/info/Licenses.aspx .
(Validate HTML and CSS ).
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