At the end of the item "Spam Spat" on TVNZ's Fair Go program, the team provide some helpful advise to consumers who are plagued by spam email. They tell you to use the "unsubscribe" button required by law - or just to reply to the sender asking to be taken off the list.
This is fine as long as the email in question is legitimate advertising, however, spam is mostly unsolicited email of a range of types, including malicious email disguised as something else.
Malicious spammers love to be replied to. If you send them a "please unsubscribe me" letter, they will just subscribe you to every spam merchant they work for. It means that the email account is active you see, so there is someone reading the mail. It does not occur to them that you don't want to get it in the first place.
Really malicious spammers will include an "unsubscribe" button which actually installs malicious software like viruses or keyloggers or permanent cookies.
1. Never reply to spam
2. Never click on anything in spam
In general - never receive html or "rich text" emails. These allow images and buttons and so on to appear in an email - you don't need them to read your mail so don't enable them. Nobody ever got a virus off plain text. You'll still be able to read the email, it just won't be as pretty.
If the spammer follows NZ guidelines, then they will have a clearly identifiable company in there someplace. If you want to unsubscribe, and you have think the company is legitimate, then google for the company name online, browse to their company web page, and use their feedback form. It's not as easy as replying, but it is better than having a some criminal run up large debts against your name or finding out your computer has been used to spam millions of other internet users.