Permissive Licenses
Permissive licenses are very flexible. They allow you to do almost anything with the code, including using it in your own projects, modifying it, and distributing it, even in closed-source projects. The only requirement is usually to give credit to the original authors. Examples include the MIT License and the Apache License.
Copyleft Licenses
Copyleft licenses are strict. They allow you to use, modify, and distribute the code, but with a catch: any modifications or new projects based on the original code must also be open source and use the same license. This ensures the code remains free and open for everyone. Examples include the GNU General Public License (GPL).
Creative Commons Licenses
Creative Commons licenses are used mainly for creative works (like images, videos, and documents) rather than software. They offer various levels of freedom, from allowing any type of use as long as you give credit (CC BY) to more restrictive options like only allowing non-commercial use or not allowing modifications (CC BY-NC, CC BY-ND).
Proprietary Licenses
Proprietary licenses are the most restrictive. They usually mean you can use the software, but you don't own it. You can't see or modify the source code, and there are often limitations on how and where you can use the software. Examples include most commercial software like Microsoft Windows or Adobe Photoshop.
Data-Specific Licenses
Data-specific licenses are designed for datasets rather than software. They define how you can use, share, and modify the data. Some are very open, like the Open Data Commons licenses, while others may have more restrictions, often depending on the data's source.
Public Domain
Public domain means the work is free for anyone to use in any way they want, without any restrictions. The author has given up all rights to the work, allowing it to be freely used, modified, and shared by anyone. An example is the CC0 license.
Dual Licensing
Dual licensing means a project is available under two different sets of terms and conditions. For example, it might be available under both a permissive open-source license and a proprietary license. This allows users to choose the license that best fits their needs.
Multi Licensing
Multi licensing involves offering the same project under multiple licenses. This is common in projects with multiple components, each of which might have different licensing requirements. It provides flexibility for users who may need to comply with various legal requirements.
Shared Source Licenses
Shared source licenses are a mix of open and proprietary licensing. They allow users to view the source code and make modifications, but often with more restrictions than open-source licenses. These licenses are typically used by companies wanting to share code with certain communities without making it fully open source.
Legacy Licenses
Legacy licenses refer to older licenses that are no longer commonly used but may still apply to older projects. These licenses might have specific terms that were standard at the time but have since been replaced by more modern licensing options.
Sector-Specific Licenses
Sector-specific licenses are tailored to meet the needs of specific industries or fields. For example, licenses for bioinformatics projects or data science applications might have terms that address the unique requirements of these sectors, such as data sharing or research collaboration.