The key innovation in these licenses is their ability to use the power held by the copyright holder—the power to restrict the flow of information—and turn that around (“intellectual jujitsu,” in a Stallman phrase) so that it enforces openness in spreading information and content.
Licenses can do that precisely because they are flexible—they can be drafted in any number of ways to require specific conditions before the follow-on user can perform any of the acts (reproducing, distributing, adapting, etc.) reserved to the copyright holder. Since the license governs an exchange—adherence to certain conditions in return for copyright permissions—violating those conditions makes a user liable for copyright infringement, and all its subsequent penalties.
Those penalties include statutory damages—fines that are set regardless of how much financial harm the infringement caused. In contrast, when a typical contract is breached, the responsible party just has to pay the cost of what was lost due to the breach. This can create some problems when the contract involved essentially giving something away gratis, the way a lot of free software does. (For the legally-inclined, there's also the problem of whether there was adequate consideration, but that's a discussion for another time.) If I gave away my software at no cost, what have I lost if someone didn't follow the rules I set out for it?
On the other hand, if that other person has infringed my copyrights, I can get a court to force them to follow the rules, as well as a minimum of $750 (and a maximum of up to $150,000), without showing that I've lost any money at all.
Obviously, the high ceiling of statutory damages can lend itself to abuses (and we've had quite a bit to say about that before), but having some level of statutory damages does give free software developers and Creative Commons-using artists a way to enforce their rights and ideals.
So in this context, it makes good sense to have licenses be flexible and enforceable with the full weight of copyright law. But how does that square with some of the issues we've raised before with overly-restrictive software licenses?
Take, for example, MDY v. Blizzard. In that case, Blizzard wants to enforce its EULA as copyright infringement, saying that users who use unapproved “bots” while playing World of Warcraft are infringing copyright. (That's the argument necessary in order for Blizzard to prevail against MDY, who makes bots, in a case for contributory infringement.) Part of the EULA is a provision saying that users can't run bots while playing. And I've argued before that this is a bit ridiculous, since under this theory, any number of arbitrary rules can be put into a EULA, the breaking of which results in liability for copyright infringement.
So how does this differ from the Artistic License at issue in Jacobsen v. Katzer?
The key difference between the license in MDY and the license in Jacobsen isn't so much what they sought to prohibit (using bots, failing to attribute and document changes), but what they offered in return. Jacobsen's license was, in exchange for meeting his conditions, granting the ability to reproduce, and distribute modifications of, his software. In exchange for meeting its conditions, Blizzard was offering merely the use of their game.
What Jacobsen was actually offering in his license were rights that are covered by copyright law—the right to copy and remix his work. Blizzard, by contrast, wasn't giving a license to copy—merely a license to use. The mere use of a work isn't covered by copyright law, so if I fail to live up to my end of the bargain, I may be violating an agreement I have with Blizzard, but I'm not infringing their copyrights.
Blizzard, of course, argues that its license was offering the user a right protected by copyright—the right to copy the game into RAM. But as the law indicates, that's not a right that Blizzard has to begin with. The owner of an individual copy of the software has the right to make whatever copies are necessary to run the program and use it—a copyright owner can't double-dip by charging for necessary RAM copies, and they can't extract additional restrictions on use the same way.
So I'm extremely happy with the outcome of the Jacobsen case—not only does it reaffirm the freedom of creators to enforce openness in the use of their works, it also doesn't needlessly inhibit the freedom of users to use those works, either.