Permission and Spam

The Complete Guide to Email Marketing

You Should Only Send Bulk Emails to People Who Are Expecting It from You and Specifically You.
It's really that simple. There are stiff legal penalties for breaking the law when you cross certain lines. But it's also possible to experience severe consequences when you comply with the law, but don't use best practices. Reputable email marketing companies will hold you to these best practices so that they can ensure delivery of your email newsletters and those of all their other clients.
Terms You Must Know – No Exceptions:
Having permission to send any recipient bulk emails is more than a key to success, it's required. It's helpful here if we examine some terms:

Spam - The sending of unsolicited email in identical or near identical form to a list or group of people.
Opt-In - This means that a person has explicitly consented or given permission to be sent bulk email from the sender.
Double Opt-In (or Confirmed Opt-In) - In this preferred method of obtaining permission, the person signs up for email contact via form, check box, sign up box, etc. A second step is added in where the person responds to a verification email before any email marketing is sent.
Opt-Out (or Unsubscribe) - The action a person takes when they no longer want to receive email from a company. It requires a web-based mechanism by which people can ask to be removed reliably from an email list. This request must be honored within ten days. Your email service provider should provide this for you automatically.