I don't think there's a way of reducing spam, only lowering the rate it increases at.
You have some companies who sell loads of email addresses to spammers, and if someone clicks a link, they know that email addy is active, so they're more likely to give that address to spammers, but if they don't know if your account is used (active) then you're probably going to get less spam.
You could always get a new email account with an obscure address, that way you're gonna get hardly any spam.
