We live in a very interesting world, which all work is kept under control of the creator. Many people (mostly corporations), say this is a good thing, and actively work to extend copyright control. Currently, the life of copyright is well past the life of the creator himself. If one makes a more thorough evaluation, one finds that copyright actually inhibits the growth of new content. In a way, all new content builds on old content, from Disney movies, to artwork, to pieces of software. This last example is an interesting one, as all pieces of software share certain similarities. After all, there are only so many was to write a sort, algorithm, or search. This has lead software into becoming a grey area for a lot of copyright. Many people are fine with sharing their software, however, and want to put their software out there for others to hack on, and a software license will allow people to do that. To use a license, people can simply include the license with the source and the binary files, to show users what rights they have. There are many different types of software licenses, and here is a quick sampling of the most common ones.
The following information is not a substitute for the actual license. For more information, read the full legal text of each license.
The MIT license is probably the easiest to understand: It lets users do anything with your code, as long as they don’t sue you. Large projects don’t use this license too much, as it gives the user absolute freedom to do whatever they want with your software, such as distribute it at a cost or rebrand and redistribute it. It’s a good choice for those who just want to publish a small project to the world, and don’t care about what happens to it whatseover.
The Apache license is very similar to the MIT license, and is used by Apache Free Software projects, such as Hadoop and Apache Web Server. The major differences are that the Apache License gives away Patent rights, and forbids the use of trademarks in derivative software. Use this if you are concerned about the previous two key differences. If you are looking for an alternative, the BSD license might work for you as well!
The Mozilla License is used by Firefox and other Mozilla products. It adds a few more restrictions on the more permissive licenses, by requiring that the source must be disclosed with all future derivatives. This prevents companies from using the program within their software suite (and selling it), without giving away the free source and the binaries of the original program.
The GNU License applies even more restrictions by saying that future derivatives or works that use the software must be licensed with the GNU GPL or other free software licenses. This license prevents other companies from using your software in a situation where users are denied the freedoms that you give them in your license, which furthers the open source software movement. However, this can be a downside for people who want their work to be used in proprietary situations, such as most commercial ones. All GNU projects are licensed under this license, such as gimp, gcc, and almost all utilites found in a GNU/Linux system or a GNU Operating System.
– [onion] chesse