Re: spam email
Never used it but the principle is simple enough - you get a separate, temporary email address that you can use to sign up to a site. If this email address then gets sold to hundreds of spam mailing lists it's not an issue since by then it will have disappeared.
It's an effective way of trying to prevent spam yes - but it won't stop it coming into your existing email account.
Save the whales, feed the hungry, free the mallocs.