Jamie Boyle’s sensible defence of open-source software starts in a disarming way, by suggesting that the Federal Circuit’s decision in Jacobsen v Katzer, which upheld the validity of an open-source copyright claim, was one of those dry-as-dust decisions that only intellectual property geeks could love. But, as he quickly points out, the decision is not just about model trains and the computer systems that control them. It is rather about the ways in which new technology is distributed from their creators to, well, just about everyone else.

Here, as in so many cases, the choice of remedy matters as much as the nature of the violation. The defendants conceded that they did not observe the conditions of the licence, including publication of the names of the original authors of the software program. But their attitude was “no big deal”, because the fanciers of open source could not prove that they suffered harm from this violation. They plumped for letting the plaintiffs get only a breach of contract remedy, one that carried with it no provable damages.