What happens to a persons contact details if they unsubscribe?
When a contact unsubscribes, their details are non-erasable. Because of the possibility that unsubscribers may be accidentally imported into the system at a later date, unsubscribed contacts are retained by the system. Cross referencing occurs during contact import to ensure unsubscribers never receive unwanted messages. This suppression of unsubscribers is a recommendation from the Guidance to the Privacy and Electronic Communications (EC Directive) Regulations 2003 published by the Information Commissioner (Data Protection).
