A Free License is legal language that sits on top of copyright. In our current copyright regime, everything is copyrighted whether you want it to be or not. What I'm writing here is copyrighted, even though I don't want it to be. There is currently no way to “opt out” of copyright. All I can do is attach a “Free License” to the work, that grants users some of the fredoms that copyright automatically takes away.
A Free License guarantees the Four Freedoms of Free Culture:
1. The freedom to view, hear, read, or otherwise attend to the Work;
2. The freedom to study, analyze, and dissect copies of the Work, and adapt it to your needs;
3. The freedom to redistribute copies so you can help your neighbor;
4. The freedom to improve the Work, and release your improvements to the public, so that the whole community benefits
Creative Commons is the most famous brand of Free licenses, however most Creative Commons licenses are not Free! Just because a license is branded Creative Commons does not mean it's free. In fact most Creative Commons licenses have restrictions that are incompatible with Free Culture.
The 3 Free licenses Creative Commons offers are:
If you see the letters -NC or -ND anywhere in a Creative Commons license, it is not a Free license. Be careful – use only one of the above Creative Commons licenses, otherwise your work will not be Free and you may alienate those fans who could help you the most.
Other Free licenses for cultural works include the Free Art license and the WTFPL.
Because all licenses ride on top of copyright, they can be seen as validating or extending the reach of Copyright law. For those who are totally fed up with existing laws and the interference of lawyers in the cultural sphere, a “non-license” may be preferable. Non-licenses are not licenses, they are statements of intention: that the artist wants their work to be copied. They don't ride on top of any existing laws, and attempt to avoid law (and the state force that backs it up) altogether.
Our favorite un-license is the Copyheart, which looks like this:
♡ Copying is an act of love. Please copy and share.
But there are others, like Kopimi, and of course you can write your own!
Whether you use a lawyer-approved Free License or a non-license, it's crucial to let your audience know they are Free to copy, share, and build on your work. While it's tempting to ignore copyright altogether, your audience can't know your work is Free unless you tell them. Try to include either a notice of Free license (i.e. “CC-BY-SA”) or a Copyheart message (“♡ Copying is an act of love. Please copy and share") wherever you post your work.
More about Free vs. unFree licenses here: