# Open Source Software: What It Is and Why It Powers the Internet

> The majority of the internet runs on open-source software. Here is what that means, why companies give code away for free and how the model works.

*Section: Technology — By Amelia Hart (Technology Correspondent) — Published December 18, 2025 — 1 min read*

Canonical URL: https://dailyjunction.co.uk/technology/open-source-software-explained
Tags: open source, linux, github, software development, technology

## Key takeaways

- Open source software has its source code publicly available — anyone can inspect, modify and distribute it
- Linux underpins the vast majority of web servers, cloud computing infrastructure and Android smartphones
- Companies contribute to open source for multiple reasons: talent acquisition, ecosystem development, avoiding reinventing common infrastructure
- The OSI (Open Source Initiative) maintains definitions and approved licences for what qualifies as open source

## What open source means

Open source software has its source code made publicly available under a licence that allows anyone to inspect it, modify it and distribute modified versions. This is distinct from proprietary software, where the source code is a trade secret and users receive only compiled binaries. The Open Source Initiative maintains a definition of open source and approves licences that meet it.

## Why Linux matters

Linux is the most important piece of open source software ever created. Linus Torvalds released the first version in 1991; today, Linux underpins the vast majority of web servers, all major cloud computing providers run their infrastructure on Linux, Android (which runs on around 73% of smartphones) is built on the Linux kernel, and Linux powers everything from routers to supercomputers. Understanding why Linux succeeded — a community of contributors collaborating across organisations and countries, no single owner, a meritocratic contribution model — illuminates the dynamics of open source more broadly.

## Why companies give code away

Large technology companies invest heavily in open source, which seems paradoxical. The reasons: contributing to shared infrastructure means not having to maintain forks in isolation; open source projects attract talented engineers (who prefer working in public); open source components become de facto standards that their originators have influence over; and open source creates ecosystem effects that benefit the originators's commercial products.

## The licence question

Open source licences vary significantly in their terms. "Copyleft" licences (like the GNU GPL) require that derivative works also be released under the same licence — meaning anyone who incorporates GPL code into their product must release their modifications as open source. "Permissive" licences (like MIT and Apache) allow incorporating code into proprietary products. Companies often prefer permissive licences for components they contribute to.

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## Sources

- [MIT Technology Review](https://www.technologyreview.com)
- [Wired UK](https://www.wired.co.uk)

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Daily Junction — https://dailyjunction.co.uk/technology/open-source-software-explained