E.g. when using this URL http://www.3cx.com/blog/webrtc/webrtc-secure/ it added https://plus.google.com/+3cx-Global/ as a publisher.
Both Facebook (open graph) and google have been trending towards putting links in as metadata, with the idea that the link contains the metadata rather than the tag itself. ('knowledge graph') So for instance, in "publisher" field, there will be a link to the google plus page or facebook page of the publisher rather than the text name. We should follow these links to get the publisher name. For the time being, finding the title is probably sufficient; although in some case, particularly with facebook, we can expect these to have the open graph type "profile" in which case the page is pointing to a person.