Not all spamming is illegal, but it is almost always unethical. These people tend to be sociopathic. They honestly don't care what harm they do; seriously, it's not just that they are oblivious to it - they know what they are doing is unethical, but they have no ethics.

Let's look at it. They buy an email account which is cheap or free. They acquire a list of addresses which can cost something, but which can be created on one's own with a staggeringly trivial amount of skill programming. They produce bulk emails which are usually mailed out for free. They send email to 10 million users which is costs them no more than sending a msg to an individual. If even one of those 10 million buys viagra or phone sex or tooth whitener or whatever it is, this fellow has made money for his client.

The most important thing any of us can do is NEVER - not even one time - should we EVER buy anything through these vermin. It's NEVER a good idea to trust them. EVER. The next step is to avoid ever opening their emails. This is not always easy, because the slimeballs KNOW that most people don't want to read their crap and will use subject titles to trick you into reading them, "The money I owe you" or "Regarding the conversation we had last week" or something like that.

The next thing to do is to complain - to your sys admin, to ISP they're spamming from. Google and MS frown on sending spam from their accounts.

Finally, when the time comes, tell your congressperson that corporal punishment is the only thing these guys will ever understand. We don't fine some tiny portion of the money they made stealing other people's time and money. We don't give them wimpy sentences that will get reduced to a few months.

Step one. ALL of their assets get seized - just as if they were drug dealers.

Step two. Bring back flogging. Every single one of them, if found guilty, gets a serious, daily flogging, throughout their long, hellish sentence.

Step three. When they complete their sentences, they get ankle bracelets and mandatory lifetime probation. They are no longer permitted to use computers; failure to comply even once results in a repetition of their last prison sentence.

I also strongly recommend handling certain other sociopathic lowlifes in the same way: certain realtors, insurance scammers, corporate execs, etc.