"Open source" generally refers to software that has been released to the public under the General Pubic License (GPL), allowing unrestricted use of, and modification of, the software code. One of the few stipulations is that any modification or enhancement to the code must also be released under the GPL, allowing communities of programmers to contribute to the development of open source software.
For us non-developers, it means we can download and use the code in any way we see fit – for free.
Releasing software to the open source community can make a sensible business model. Companies distributing open source software don't make money off the software code itself, but they can earn substantial revenue from services to enterprises (consulting, customization, training, support).
Because of its transparency, the source code being freely available to both hackers and developers, open source can be more secure than traditional software. The more eyes looking at the code, the more likely that a security hole will be identified and plugged before it can be maliciously exploited. However, not every bit of code labeled as 'open source' is good code, just as much well-known traditional software still requires frequent patches and security updates.
One big advantage with open source is that you're not reliant on a traditional software company. For instance, Microsoft ends support for software after 7 years in most cases, forcing you to purchase an upgrade. Large, traditional software companies can also go out of business or be gobbled up by a competitor, affecting support for software that may be crucial to your business. Even if an open source project ends, the code is freely accessible for a programmer to continue to provide support.
While the open source development model can produce software as stable and secure as traditional software companies, not every piece of software produced under either model will be stable and secure. Anyone who's seen the 'blue screen of death' knows that!
However, considering an open-source alternative can save money, provide innovative new features, and offer better security for your small or home-based business. They can also offer compatibility across different operating systems, meaning your business can run the same software on Windows, MacOS, and Linux machines.