There are two different kinds of permission when it comes to collecting and sending to email addresses: Express consent and implied consent.
Express consent means that your contacts have opted into your marketing communications by giving you explicit and unquestionable permission to send them email. Your contacts must complete an action such as providing written consent, or filling out an opt in form, in order to remain on your marketing list. When obtaining express consent, you must be clear in your intentions and inform your contacts about who will be sending emails to them by providing your name, company name, company address, company website, company phone number, and company postal address. You must also provide the name of the email provider that will be sending the emails and let your contacts know that they have the ability to unsubscribe at any time.
Implied consent means that you have reason to believe you have permission to send them messages. You may have had a prior business or non-business relationship with a contact but have not obtained express consent to send them emails.
Important note for Canadian subscribers: as per new Canadian Anti-Spam Legislation, implied consent does expire after a period of time. Contacts that were captured after July 1, 2014 must provide express consent within 2 years after initially collected. For more information on the CASL, please visit Basics of CASL.