I don't think the analogy between literary borrowings/influences and the posting of videos on YouTube holds up. Of course authors have used and adapted others' ideas and stories to create their own fictions from time immemorial - after all, there are only a few original plot lines in the whole of literature - but this is simply not the same as taking a DVD, cutting out a bit of it and then posting the cut-out clip on YouTube without the DVD creator's permission. (And even in the literary world, authors have been sued by other authors for alleged plagiarism - the recent "The Da Vinci Code" legal wrangle was a case in point.)

The argument can go on for ever and ever - but the analogy doesn't hold true.