The term "open source" refers to software that can be freely redistributed, analysed and modified by anyone. Key characteristics of open source software include:

Free: The software doesn't cost anything to obtain – although there are costs involved in configuring and maintaining it, just like with other software;

Open: Because the software code is open and readable by anyone, it also means that the software can be modified by anyone with programming skills ... allowing for the translation of software into local languages or the addition of features needed by a particular group;

Collaborative: Open source software draws its strength from the fact that people who improve, modify or customise programs must give it back to the open source community so others can benefit from their work.

How does a piece of software become open source? The people who created it decided to release it under a license such as the General Public License (GPL) that meets the criteria of the "open source definition" outlined above.

It is often said that open source licensing is "viral" because people who modify a piece of software must release their modifications under the same open, free and collaborative conditions of the original software