Thanks for your comment on my blog. I’m not sure what you mean by “the provenance of the content”.

Basically, though, facts and ideas are not protected by copyright, only the particular original expression of the facts or ideas can be protected. So, when a newspaper reporter reports on facts and information gathered from numerous sites, the reporter is (usually) expressing that information in his/her own words, and thus is not “copying” the material protected under copyright law. Still, it’s often considered ‘good form’ to give attribution to one’s sources.

The difference for a play, is that the material that’s contributed IS protectable expression, and thus can only be performed with permission from the owner.
(A play is performed ‘as written’, so each performance is a copy.)