You can't always tell, which is why I said "appears to be". My intention is to delete any links to material that appears to have originated from a source other than the person posting it. In other words, if you're going to post to a clip from the tv show Good Morning America, it needs to be a link to the video on the official Good Morning America website, ABC news, an officially associated youtube channel, or a known copyright holding source such as hulu; if it isn't a link to some official source like those above, then don't post it or it will be deleted.