When a copyright holder contacts Alliance Communications, they send us the name of the material that is being infringed upon, the time that the material was being made available online, as well as the public IP address of the computer or network that is sharing it.  Since public IP addresses are unique, and can only be used on one device at a time, they act much like a fingerprint.  To be in compliance with the Digital Millenium Copyright Act (DMCA), Alliance uses this information to identify and contact the party responsible.