New submitter eporue writes: YouTube claims that I haven’t been able to prove that I have commercial rights to this video of Superman. They are asking me to submit documentation saying “We need to verify that you are authorized to commercially use all of the visual and audio elements in your video. Please confirm your material is in the public domain.” I submitted a link to the Wikipedia page of the Superman cartoons from the 40s where it explains that the copyright expired, and to the Archive page from where I got it. And still is not enough to “prove” that I have the commercial rights. So, how do you “prove” public domain status ? Read more of this story at Slashdot.