“Now, IANAL, but it looks to me that this is problematic for licences like the GNU GPL, since it means that rights aren't passed on downstream – something that is absolutely vital for free software's licensing model to function. I look forward to hearing some lawyers' views on this issue.”

Why on earth would you prefer to get a sublicense rather than a license (non-assert) direct from the patent owner?

There is no need to be paranoid. You are reading too much into the language of the GPL. You don't need a license–because OWFa gives you an even stronger promise direct from the patent owner–and the GPL doesn't care.

If you try to force the GPL into some legal formalism that requires licenses and sublicenses, you'll get an ulcer and no software. Don't worry. Under the OWFa, the patent owner won't sue you for patent infringement if you implement the specification or use such software.

/Larry

“Whenever someone conveys software covered by GPLv3 that they've written or modified, they must provide every recipient with any patent licenses necessary to exercise the rights that the GPL gives them.” (http://www.gnu.org/licenses/quick-guide-gplv3.html).

My reading there is that the person licensing under the GPL must give the patent licence, not somebody else. What's your view?

As to the language “a personal promise directly from me to you” that you mentioned, keep in mind that the promise is from “me,” the patent owner, to “you,” which is essentially anyone in the world who makes, uses, sells, or distributes an implementation of the specification. In other words, while you can’t technically pass on the patent rights in the non-assert section to another party, everyone in the world gets the rights under the OWFa anyway. This direct relationship between the patent grantor and each person is also intended to protect the community since it helps ensure that if a recipient of the patent grant sues anyone over their implementation of the specification, the patent grantor can terminate the rights they granted to the party that started the legal action. Legally speaking, this provision is avoiding what’s known as patent exhaustion.
To say this another way, this structure helps ensure that someone who non-defensively sues another person over an implementation of the specification cannot continue to take advantage of the rights granted under the agreement. OWFa is attempting to make a covered specification into a litigation free zone to the extent it can.

I think it’s also worth mentioning that the other section you noted, the royalty free patent commitment, is a right in addition to the patent non-assert. If someone is not happy with the patent non-assert, they can request a more traditional royalty free license. Think of this as a fallback. If you can’t live with the non-assert, you can still negotiate for a license, and in that case OWF leaves it to the patent holder and the recipient to determine those license terms on their own, provided those terms are, to use legal jargon, reasonable and non-discriminatory. This is another safety net for implementations.

From a copyright perspective, the OWFa allows for the creation of derivative works of the specification, provided those new projects provide attribution. From a patent perspective, the OWFa’s patent grant covers new projects to the extent those new projects maintain interoperability with the covered specification by keeping the required portions of the original specification.

This last point is actually very important and one reason why specifications require a different kind of license than source code. Source code licenses tend to be inward looking in that they cover code and what you can do with that code. Specification licenses tend to be outward looking in that they focus primarily on interoperability between different implementations of the same specification. For example, from a source code perspective, it’s fine if you take an Apache web server and tweak or change the code since it doesn’t adversely impact anyone. If, on the other hand, you were to decide to unilaterally change how the server output HTTP, you’d be breaking interoperability with every browser that is expecting to receive the HTTP standard. This would harm the entire ecosystem built around that specification.

The reason people come together to agree on a standard is for interoperability, and often times that agreement is based on any number of compromises. When a patent owner commits to making their patents available for a specification, it’s in exchange for interoperability with other implementations of the same specification. The OWFa tries to strike a balance here. The agreement allows anyone to take the specification and change it any way they’d like, but to respect the compromises and agreements that went into the specification and the ecosystem built around the specification, you can only take advantage of the patent grant for those derivative works that maintain interoperability.