Each email you send through little green plane has an unsubscribe mechanism that will automatically remove contacts from your mailing list. You must provide an unsubscribe mechanism by law. Even if you accidently upload an unsubscribed contact to your list, you are safe in the knowledge that we will not allow you to send an email to that recipient again, ensuring you are data protection compliant. If someone unsubscribes, make sure you do not email them. Using the automatic unsubscribe facilities offered by the standard little green plane footer means all unsubscribes will be permanently removed from future campaigns. It is also wise not to use purchase lists if you can possibly avoid it. Make your opt-out links clear, not hidden in the email. Take the standard approach and have this at the bottom of your email, where most people expect it to be.
Never send to anyone who has unsubscribed, bounced or marked one of your campaigns as spam with little green plane’s Do Not Mail list feature.
If you are going to send email marketing campaigns, legally you need to provide a way for your subscribers to opt-out of your mailings if they want to.