Now, one technical problem is how to associate in a reliable way the owner of an object with the subject that created it. I started to think about the problem early this morning while running in Pisa under a light rain. The run was amazing good, and I felt very good after 7 kms.
My first thought was that I can simplify the problem if I just focus on Web pages (a type of object), because almost all the other objects (images, videos, audios) are generally embedded in web pages.
My second though was that all the Web pages belongs to a domain. Therefore, I can check whether the subject claiming the ownership has email access to that domain by sending an email and asking for an explicit acknowledgement. After all, Facebook adopts a similar solution for checking the rights when you want to declare your (work) affiliation. This solution may work but has the problem of discriminating the ownership for multiple users belonging to the same domain. It works for affiliation, it does not work for ownership.
My third thought was that the owner of a page has, by definition, edit rights on it. Any owner can edit her own pages. Therefore, she can embed a special tag with an unique id generated for checking the ownership. Whoever wants to check the ownership can, therefore, check the presence of this tag and verify the ownership.
Now, if you think about it you can ask yourself if you have seen this elsewhere. In a sense, Facebook is already adopting a similar principle for their Like buttom which must be generated ad-hoc for each specific page. Therefore, Facebook can check the ownership of a page once the like button is embedded in the page, because only the owner can edit the page.
Apparently, Facebook is not exposing this feature because the Like button is "only" used by other people for express their preference on a page (an object), instead of checking the ownership of the object itself.
Anyway, this could be a good feature: Giving the opportunity to all the Web page owners to annotate their pages with their facebook profile. In my lingo associate any object with the subject that create it.
PS: here it is the like button generated for this particular URL. I certify the ownership of the page by embedding the button