What is open-source software?

One of the more interesting models for content creation that accompanied the birth of the internet is open-source software. In the open-source community, software artifacts are given away for free-​although licensing terms vary. The open-source model provides vibrant proof that there are many different ways to incentivize people to build and create things-​and that money is just one of them. Even without direct payment, many contributors to the open-source community are well-compensated, both in fame and fortune.
Credits: Talking: Geoffrey Challen (Assistant Professor, Computer Science and Engineering, University at Buffalo). Producing: Greg Bunyea (Undergraduate, Computer Science and Engineering, University at Buffalo).
Part of the www.internet-class.org online internet course. A blue Systems Research Group (www.bluegroup.systems) production.

[@mikewatson2270]

You didn't mention the GPL license. GPL licensing is what keeps Microsoft and Google from copyrighting your free software and then suing you for using it unless you pay up. The Linux kernel and the GNU operating system almost everybody runs on Linux have a GPL license for very serious reasons. It was a lesson learned through hard experiences and a lesson that many programmers and users still don't understand.