Damn, that's the name of the startup? I was searching around for my pitchfork. > The pitch of the audio in this video has been slightly altered by Motherboard

Damn, that's the name of the startup? I was searching around for my pitchfork. > The pitch of the audio in this video has been slightly altered by Motherboard to protect a source. How does this work? Do they sort of broadcast some unique audio/video to each viewer in order to trace leaks? Is this a standard practice? Is there some service that offers this?