The article somewhat overstates the significance of this case in terms of precedential value.
On a procedural level, understand that this is a district court opinion and is not binding on any other court. Of course, if other courts find the arguments persuasive, they can adopt the reasoning. But no court has to adopt the reasoning in this opinion.
On a substantive level, it's important to look at the arguments the court is addressing and how they are addressed:
1) Did the plaintiff adequately allege a breach of contract claim?
We're at the motion to dismiss phase here and the court is only looking at plaintiff's complaint and accepting all of the allegations as true.
There are essentially only 2 arguments the court addresses: A) Was there a contract here at all?; and B) Did the plaintiff adequately allege a recognizable harm?
Understand that in a complaint for breach of contract, a plaintiff has to allege certain things: (i) the existence of a contract; (ii) plaintiff performed or was excused from performance; (iii) defendant's breach; (iv) damages. So, the court is addressing (i) and (iv), which I refer to as (A) and (B) above.
As to (A), the argument the defendant appears to have made is that an open source license is not enforceable because a lack of "mutual assent." In other words, like a EULA or shrink-wrap license, some argue that an by using software subject open source license doesn't demonstrate that you agreed to the terms of that license.
The court, without any real analysis, says that by alleging the existence of an open source license and using the source code, that is sufficient to allege the existence of a contract. The court cites as precedent that alleging the existence of a shrink-wrap license has been held as sufficient to allege the existence of a contract.
But the key word here is "allege." As the case proceeds, the defendant is free to develop evidence to show that there was no agreement between the parties as to the terms of a license. So, very little definitive was actually decided at this stage. All that was decided is that alleging that an open source license existed is not legally deficient per se to allege the existence of a contract.
As to (B), defendant apparently argued that plaintiff suffered no recognizable harm from defendant's actions. The court held that defendant deprived plaintiff of commercial license fees.
In addition, and more important for the audience here, the court held that there is a recognizable harm based on defendant's failure to comply with the open source requirements of the GPL license. Basically, the court says that there are recognizable benefits (including economic benefits) that come from the creation and distribution of public source code, wholly apart from license fees.
This is key - if the plaintiff did not have a paid commercial licensing program, it could STILL sue for breach of contract because of this second type of harm.
That being said, none of this argument is new. There is established precedent on this point.
2) Is the breach of contract claim preempted?
Copyright law in the United States is federal law. Breach of contract is state law. A plaintiff cannot use a state law claim to enforce rights duplicative of those protected by federal copyright law.
So, what the court is looking at here, is whether there is some extra right that the breach of contract claim addresses that is not provided under copyright law.
In other words, if the only thing that the breach of contract claim was addressing the right to publish or create derivative works, then it would be duplicative of the copyright claim. And, therefore, it would be preempted.
Here, the court held that there are two rights that the breach of contract claim addresses that are different from what copyright law protects: (A) the requirement to open source; and (B) compensation for "extraterritorial" infringement.
The real key here is (A), not (B). With respect to (A), the court here is saying that the GNU GPL's copyleft provisions that defendant allegedly breached are an extra right that is being enforced through the breach of contract claim that are not protected under copyright law. Therefore, the contract claim is not preempted.
(B) is a bit less significant for broader application. What (B) is saying is that because the plaintiff is suing for defendant's infringement outside the U.S. ("extraterritorial" infringement), and federal copyright law doesn't necessarily address such infringement, that's an "extra element" of the breach of contract claim. I say this is less significant because it wouldn't apply to a defendant who didn't infringe outside the United States. So, if you were the plaintiff here and the defendant was in California and only distributed the software in the U.S., argument (B) wouldn't apply.
I hope this clarifies what is/is not significant about the opinion here.