The Legal Layer Beneath the Download Button
Every piece of software you use is governed by a license that specifies what you can and can’t do with it — run it, copy it, modify it, share it, use it commercially. Most software users never read the license (clicking ‘I agree’ without reading is so universal it’s been the subject of research demonstrating that people would theoretically agree to surrender their firstborn child for software access), but the license determines important things about the software’s availability, cost, and future.
Open source licenses specifically have created the software ecosystem that modern technology depends on — the Linux kernel, Python, React, PostgreSQL, WordPress, Android’s Linux foundation, and thousands of other foundational components are open source. Understanding what open source means, the differences between open source license types, and what they mean for users (both individual and organizational) provides a more informed basis for choosing and using software.
What ‘Open Source’ Actually Means
Open source software is software whose source code is publicly available under a license that permits users to view it, modify it, and distribute the modifications. The ‘open’ refers to the source code being open for inspection and modification, not to the software being free of cost (though most open source software is free to use). The Open Source Initiative maintains the definition: a license must meet ten specific criteria to qualify as open source, including free redistribution, available source code, and no discrimination against persons, groups, or fields of endeavor.
The distinction from ‘freeware’ or ‘free software’: freeware is software distributed at no cost but with source code not available and modification not permitted. Open source may or may not have usage cost (most is free; some open source licenses permit commercial products based on open source code) but the defining characteristic is source code availability and modification permission.
The License Spectrum: Permissive to Copyleft
Open source licenses range from permissive to copyleft (also called ‘viral’ licenses). Permissive licenses (MIT, Apache 2.0, BSD) allow anyone to use the software for any purpose, modify it, and distribute modified versions under any terms — including proprietary, closed-source products. This is the license type that commercial software vendors most prefer to use in their products, because it allows incorporation without requiring them to open-source their own code.
Copyleft licenses (GPL, LGPL, AGPL) require that any software distributed that incorporates or modifies the licensed code must be distributed under the same license terms — making the ‘open’ nature ‘viral.’ The GPL license that covers the Linux kernel means that software that incorporates Linux kernel code must also be GPL-licensed. This is why Android (which uses the Linux kernel) is available as open source, but the proprietary Google apps that run on Android are separate from the kernel.
What Open Source Means for Business Use
Organizations using open source software in commercial products need to understand license obligations before incorporating open source components. Permissive-licensed components (MIT, Apache) can be used in commercial products with minimal obligation (typically: include the license text in documentation). GPL-licensed components incorporated into commercial products may require open-sourcing the commercial product’s code — which most commercial software companies strongly want to avoid.
The AGPL (Affero GPL) adds network use to the copyleft trigger: software that uses AGPL code as part of a network service must make its source available. This is why many commercial SaaS companies avoid AGPL-licensed dependencies and why some open source companies use AGPL specifically — it prevents competitors from running their software as a service without contributing back.
Practical Implications for Individual Users
For individual users (rather than businesses incorporating open source into products), open source licenses have few practical restrictions on use. You can use LibreOffice, VLC, Firefox, Linux, GIMP, and any other open source software for personal and commercial work without license concern. The license restrictions primarily apply to redistributing the software or incorporating it into your own software distributions.
The practical benefit of open source for individual users: transparency (the code can be inspected for security and privacy), longevity (open source projects can be maintained by communities even if the original creator stops; proprietary software can be abandoned with no way to maintain it), and freedom from vendor lock-in (you can run the software without an ongoing subscription or the vendor’s continued operation). These practical benefits explain why security-conscious users and privacy-focused individuals often prefer open source alternatives even when proprietary alternatives are available.