Yesterday the open source world got handed a major victory in the courts -- or, rather, given another brick for its growing wall of legal defense. The Federal Circuit Court of Appeals has ruled that the use of content under a properly worded open license is still protected by copyright law.

The case in question, Jacobsen v. Katzer, involves just such an issue. Jacobsen created an open source software package to control model trains; Katzer allegedly created a derivative product that used Jacobsen's work but didn't hew to the attributive licensing clauses that came with it. Jacobsen then took Katzer to court for copyright infringement, and further claimed that his licensing terms were unambiguous enough that it should have been clear he wasn't surrendering copyright on the material in question by offering it under the terms of such a license. (Jacobsen could, in theory, have sued for breach of contract a lot more easily, but the copyright terms of this type of case have, as far as I know, generally gone untested.)

The courts agreed on that point, and so did the appeals court. In the text of the judgment, the court noted:

The clear language of the Artistic License creates conditions to protect the economic rights at issue in the granting of a public license. These conditions govern the rights to modify and distribute the computer programs and files included in the downloadable software package. The attribution and modification transparency requirements directly serve to drive traffic to the open source incubation page and to inform downstream users of the project, which is a significant economic goal of the copyright holder that the law will enforce. Through this controlled spread of information, the copyright holder gains creative collaborators to the open source project; by requiring that changes made by downstream users be visible to the copyright holder and others, the copyright holder learns about the uses for his software and gains others' knowledge that can be used to advance future software releases.

It's striking, and rather reassuring, that the court not only took the time to educate itself about the subject but understands the deeper implications of what's going on. Making something available free of charge does not necessarily dilute its value; in fact, it may augment it, especially if the people who acquire it are building on it and returning those changes to the world at large.

What's still up in the air is whether or not Jacobsen is owed damages. I suspect such a thing would be established on a case-by-case basis, as fits the event in question. But open licensing in general just took a massive and well-deserved step forward.