Since OSPs are often protected by Safe Harbors, what's left for copyright owners is often to go after the users who post or download infringing content. This can be difficult as copyright owners often have trouble tracing users back to real people, however they are not without tools.
Section 512(h) gives copyright owners the ability to issue subpoenas to internet service providers to identify subscribers. However, a subscriber identifies only the household or institution that is assigned the offending IP address, and an IP address is not a person. Copyright owners still face the challenge of identifying which individual was using the internet connection at the time infringement was committed.