"Copyleft is a general method for making a program or other work free, and requiring all modified and extended versions of the program to be free as well. The simplest way to make a program free software is to put it in the public domain, uncopyrighted. This allows people to share the program and their improvements, if they are so minded.

What is free knowledge? What is a free encyclopedia? The essence is something that anyone who understands free software can immediately grasp. A free encyclopedia, or any other free knowledge, can be freely read, without getting permission from anyone. Free knowledge can be freely shared with others. Free knowledge can be adapted to your own needs.

There is this ludicrous paradigm among the technorati that just because a piece of software is developed collaboratively and by enthusiasts with source code shared freely on the web, that automatically makes it more secure and less buggy.

Free software is software you can study, modify and share without restriction. But unlike proprietary software, there is no big budget marketing campaign behind it. Rather, people discover it and come to value the freedom it provides. What are these people's motivations for working on free software? Why is community and sharing so important? Why should everyone be using free software?

Now comes a new rallying cry: software wants to be free. Or, as the tech insiders say, it wants to be “zero dollar.”

A growing number of consumers are paying just that — nothing. This is the Internet’s latest phase: people using freely distributed applications, from e-mail and word processing programs to spreadsheets, games and financial management tools. They run on distant, massive and shared data centers, and users of the services pay with their attention to ads, not cash.

While such services have been emerging for years, their rapid adoption has been an important but largely overlooked driver of the $44.6 billion hostile bid that Microsoft made to take over Yahoo this week.

"Today marks the twenty-fifth anniversary of the initial announcement of the GNU Project, a pioneering initiative to develop an operating system that gives all users the freedom to modify it and publish modified versions, individually or working together.

One of the most significant moments in the history of the modern software industry took place in 1998 when Netscape announced plans to release the source code of its browser under a license that would freely permit modification and redistribution.

"Freedom is... the GNU Operating System. GNU is the first operating system designed to give you, the user, the freedom to share, study and modify it. We call this free software, because the user is free. GNU and free software are used by millions of people all over the world.

Cristobal Palmer got very agitated when those "cannot read file" boxes popped up on his computer - until he found out they could make him thousands of dollars. The all-too-familiar messages helped spark Palmer's interest in open-source software, programs that are written to be shared with and modified by others.