The GNU General Public License (GPL) is a free (as in freedom) software license that is used by many open source projects, including WordPress. While many of us are probably familiar with the GPL, there are also a number of misconceptions. It’s important, as WordPress professionals, for us to be able to talk about the GPL with our clients and coworkers -- both in terms of what the GPL says and also what it doesn't say. The GPL is based on some extremely powerful ideas, and it is a shame that they are sometimes misunderstood. If you feel like maybe you could use a refresher or some ideas about how to explain the GPL to people you are working with, this talk is for you.