Wendy Seltzer wrote:
...
The concern about limiting implied licenses is important, though. By
definition, an implied license is one that's presumed from the context
of an offering and by the absence of a contrary explicit license. If
as a factual matter, many people have been acting based on implied
licenses of broader scope than either fair use or what would be chosen
in an explicitly linked license, then you might say it's better not to
provide this encouragement to link licenses at all (and hoping that
time and general practice will morph those implied terms into fair uses).
If the rfc encourages people to add licenses, it opens up the
possibility that their explicit terms will contradict and override
what has previously been implied.
That's a worrying Heisenburg effect.
This is a critical point. Without this, implementors cannot safely
ignore licenses they don't understand (falling back to things like
"fair use" if they can't find any licenses that grant additional
copying rights). This means that implementors would likely have to
drop feeds containing new licenses on the floor, meaning that new
license schemes would never be deployed.
...
Thus, it would seem that the only effective use of the license link
is to grant rights not to restrict them.
Yes. Given the current murky and complicated legal situation with
implied licenses, fair use, etc., granting explicit and well defined
rights is a huge win for everyone.
I don't think there's a legal mechanism for telling people "you may
only use this format if you grant a license equally or more permissive
than X." (at least none short of patent claims on the format itself...)
No, but I think there may be a technical mechanism for saying "this
particular extension only lets you grant rights with each new license
link, not take them away":
...
How about (IANAL of course):
"Nor can a license.... restrict or remove any implied copy or usage
rights which would otherwise exist in the absence of the license."
The intent being that adding a license, or a new type of license, is
always safe: If what you're doing with content is allowable, if the
feed provider adds a license, it is still allowable.
There is a parallel with the principle of substitutability [1] in
software engineering, which allows extension while maintaining desirable
invariants (in this case, the ability to what one would naturally expect
to do with a feed).
[1] http://en.wikipedia.org/wiki/Liskov_substitution_principle
-John Panzer
http://abstractioneer.org
