One of our apps had its first repeat spammer to the market comments. A player of a game app (“Ronnie”) decided to spam our app twice each day for a while back in July. He was promoting his referral code the game uses as a reward. It was quite bothersome to me as I seemed powerless to do anything but remove it from my own personal device.
The support people of the app he was promoting promptly banned "Ronnie." I want to thank PerBlue.com for handling the entire incident with grace and speed.
If a user sees spam, they should tell Google. There’s a spam checkbox in the market app next to each comment. If enough people mark a comment as spam, eventually Google should take care of it.
If a developer sees spam on their app comments, they need to be proactive. I should have reacted quicker in my case and contacted the app's support people right away.