You sometimes hear people trying to dismiss the GNU General Public License, the most popular of the Free/Libre and Open Source Software (FLOSS) licenses, as being unenforceable. While there is a long list of companies that have been alleged to infringe the license, none of these companies seem to agree this license is unenforceable and opt to settle out of court rather than challenge the license.
The latest case involves Verizone. Verizon distributes BusyBox to its customers in devices that are provided to Verizon by Actiontec Electronics, Inc. In December the Software Freedom Law Center (SFLC) filed a lawsuit on behalf of BusyBox against Verizone alleging infringement of the GPL. Only a few months later they are announcing that the BusyBox Developers Agree To End GPL Lawsuit Against Verizon.
Please remember this fact when you hear people trying to dismiss the GPL as unenforceable. Some very large and successful companies have been accused of infringing the GPL, and they have all opted to comply with the license rather than challenge it. I believe they companies understand how enforceable the GPL is, and recognize they could not win against it in court.
Please also remember these cases when you hear someone claim that FLOSS is “giving away” software. Clearly there are obligations when distributing FLOSS, and that if you don’t live up to these obligations you will be challenged in court. Enforcing the terms of a FLOSS license is easier to enforce than the often partly unenforceable terms of a non-FLOSS EULA, this means you are more likely to get caught than infringing a non-FLOSS EULA. This is because the obligations created by FLOSS licenses largely only create obligations on distributors and fellow software developers, not simple end users of the software.