Google takes a sort of hard-line approach via the DMCA, telling the court that however the MPAA may try to mislead them, Hotfile is in fact protected under safe harbor provisions. And furthermore, Google suggests that the MPAA’s approach is contrary to the language in and precedents surrounding the DMCA. The onus is on copyright holders to alert a service to the nature and location of an infringement, and the service’s responsibility is to alert the user if possible and remove the material within a reasonable period of time.
We warn the reader in advance that the proof presented here depends on a clever but highly unmotivated trick. -- Howard Anton, "Elementary Linear Algebra"