ODRL can be just as terse as SPDX if one uses the odrl:hasPolicy tag to point to an external file containing ODRL. For instance, all you need is:
“odrl:hasPolicy”: “http://example.com/policy.odrl”
To make things easy for people, what we could do is define a SocialWeb profile (like the Creative Commons ODRL Profile) that includes the definition of those policies most commonly expected to be used for SocialWeb content. These policies would differ from existing ones in that they would address SocialWeb specific concerns like search-engine-index rights, etc. The ODRL-encoded policy files would be hosted at some well-known location in much the same way that namespaces, etc. are commonly hosted. Ideally, most people would select from those consensus policies, but those who had unusual requirements would be free to define them either in their entirety or as exceptions (Constraints) amending the standard policies. Over time, if patterns or trends were found in the use of Constraints, then we could add new policies to the profile and to the shared repository.
Absolutely! Of course those who want anything other than minor departures from existing, pre-defined policies should be strongly encouraged to create them in ODRL files that are referenced using by using odrl:hasPolicy, rather than embedding them in each piece of content published. One might implement instance-specific rules that say things like: “Your post will be delayed or rejected if your policy statement is larger than your message content…”
I believe ODRL covers what you’re looking for. An ODRL Asset is any resource or a collection of resources that are the subject of a Rule. Assets can either be stand-alone, or “partOf” an AssetCollection. But, since Assets can be just about anything, ODRL doesn’t define any type-specific attributes for describing or naming Assets. So, if we wanted to use hashes to identify parts of an object as individual assets, or as partOf some AssetCollection, we could define those Asset attributes in a SocialWeb profile.
Such horror stories are more likely to occur if we remain stuck with today’s human readable and often incomprehensible licences. If we can move to a requirement that grants must be machine-readable, then it will be much harder to trap or trick people. The rule for admins should be: “Don’t do anything not clearly allowed under copyright law with any object that has policies or rules that you don’t understand.” Admins might even decide to handle content with opaque policies. So, if some lawyer links to a non-machine readable license, or uses a machine-readable policy that includes non-standard vocabulary, they should expect that their content simply won’t get distribution. We can use ODRL, as a machine-readable syntax, to force people to be explicit and open about the rights they are withholding.
Remember also that, in the absence of a contract between publisher and consumer, the use of any Rights Expression Language is inherently limited to granting rights which would otherwise be withheld. Thus, the Rights Expression Language can only be used to make content more open and more freely used. Without a contractual relationship, nothing anyone inserts in their content allows them to restrict rights that are not already reserved to them by law.