As to what happens when one engages the spammers, Harvard researcher Ben Edelman, one of the most vocal critics of spyware purveyors, fell victim to a massive DDoS (distributed denial-of-service) attack over the past 24 hours. ('way back in 2005)
Edelman is a well known and respected researcher. He was among the first to discover the Sony rootkit, and the first one to make and publish a useful analysis of it.
You are unlikely to see any identification of the person(s) actually responsible, since the activity is illegal. Persons who allow their machines to be infected and used may be "morally compromised," but usually there's one person (or criminal organization) at the root of it, and only that person can be dug out and held liable.