Most people have solutions to some of the world's problems. These solutions tend to be simple, and in an ideal world would work great. The problem is that these solutions don't take the world's greatest evil into account. This evil, which is inherent in human nature as it is also one of our most powerful survival traits, is greed. Greed can be seen every time an executive takes a million dollar bonus instead of giving a small wage increase to the workers who actually make the products. The end result of greed is destruction. Greed is counter-balanced by altruism. True altruism is rare today, as there is usually another motive for the apparent altruistic act. One of the most prevalent forms of altruism today is the Open Source movement.
The idea behind open source is quite simple. Instead of keeping the source code (the magic ingredient that makes software) a closely guarded secret, the source code is given away. The instant greed response is, “but then how do you make money.” Most open source companies, and there are many that have thrived, make their money from different means. Many open source companies give their software away and make money by selling support contracts. Others survive by sponsorship (such as advertising, which is why ad blocking software is inherently evil). Some survive by donations by the community of people who use the software. Yet others survive by having closed source packages that complement their open source offerings. I am sure there are other business models that I am missing, but the point is that there are ways of making money while still being somewhat altruistic.
Open source is different from public domain material as it is still copyrighted material. The permission to distribute the source code is part of the license agreement that comes with the source code. “But I never agreed to any license,” the greedy voice says. You don't have to in order to use the software. If you are planning on giving away, modifying, or selling the software then you have a problem, as copyrights forbid you from doing any of those things. The only thing that is allowing you to do any of the above things (and a bunch of other things that I won't get into here) is the license. If you don't want to agree to the license, you can't modify or distribute the software as that would be breaking the law! There, unfortunately, are a huge number of licenses out there, but the most prevalent one is the GPL or General Public License.
We will take a look at the different licenses later, but first let us explain why Open Source is even needed. Greed, of course, has a lot to do with this, as you will see in the next section.