This is about Inducing Patent Infringement, not infringing patents
A subtle difference, but an important one.
If I make a sell and product in the US which infringes a US patent I will be in breach of that patent, irrespective of whether I knew about the patent or not. Nothing in this judgment changes that.
However, if I I make something, outside the US, and flog it to someone who imports it into the US and infringes a US person, then I will be liable for contributory infringement in the US if I knew it infringed a US patent, or if I wilfully turned a blind eye (known in English law as "Nelsonian knowledge").
Contributory infringement is a big problem for software companies: it means that if I distribute software outside the US which potentially infringes a US patent, then I can be liable for contributory infringement if I was aware it infringed, or if I turned a blind eye to infringement. This is problematical for a number of reasons:
1. If it's open source software, for example, then I am making it available for anyone to download, irrespective of their location.
2. If I can be found liable because I copy the source code (which some commentators have suggested might be the case), then essentially I am simply providing instructions for how to create the infringing invention: WHICH IS EXACTLY THE POINT OF PUBLISHING THE PATENT AT THE PATENT OFFICE ANYWAY.
3. How can I become non-infringing, if am not doing anything which infringes the patent itself in the first place? I'll never be able to get a licence from the patent holder which says I can induce people to infringe with impunity. So I suspect the only option is to say something like "this product may infringe patents in your jurisdiction. I don't know. But I am not encouraging to use it unless you are sure it doesn't infringe." I don't know if this works or not: on the one hand, by letting someone have your software with this incantation, it's pretty clear you are not encouraging to them to infringe a patent. On the other hand, the incantation is so simple, that the US courts might just see this as a transparent effort to avoid liability.
What is undoubtedly the case is that it seems to confirm that the US considers that it has jurisdiction in relation to (this aspect) its patents outside the US, even thought patents are supposed to be strictly limited to the jurisdictions in which they were granted.