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.
Angry Sniper is a very vicious and sarcastic character. In most of his appearances, mainly in BallgameOver.mp3 and the sections on killing, efficiency and CARVVER on Be the Hammer, he encourages the people reading or hearing his message to go on killing sprees or just generally be difficult for the government. He also speaks of violent "hypotheticals" that constantly involve murder.
It is currently unknown who his voice actor is.