Angry Sniper seems to be a rather prominent character in the futuristic world of Year Zero. He's featured in the BallgameOver.mp3 as well as on the Consolidated Mail Systems website. He also appears to be the one running the Be the Hammer site.
It is speculated by some that Angry Sniper is voiced by Trent Reznor himself...though others believe that it is the voice of Corey Taylor - singer for Stone Sour/Slipknot.