A reader posted a question on a Facebook group I participate in concerning email marketing. After reading the different responses to her inquiry, I decided to do a bit or research to find out from the best response to her question.
I ran across this article from the Vertical Response folks that sums up just about every you need to know about rules and best practices around 
email marketing:
It’s the Law: 7 Email Marketing Rules You Should Know
1. Tell readers where your email is coming from
The law focuses on honesty. The “From,” “To” and “Reply to” labels need to tell the recipient where the email comes from. In other words, these fields should contain the person’s name or the business name sending the email.2. Write an honest subject line
Your subject line should reflect what’s in the email. You can’t be deceptive here. In other words, don’t write “Claim your $500 gift card” in the subject line just to get people to open an email that’s really about a new product…3. Recognize you’re sending an ad
Acknowledge that the email you send is, in fact, an ad. This isn’t necessary if everyone on your list has given you permission to send emails. We strongly suggest that you get permission from all of your subscribers before sending emails….4. Give an address
Each email must contain the postal address for the person or business sending the email. It helps to show your business is a credible one, and offers another way for your recipients to opt-out of your emails if they need to.5. Every email needs an easy opt-out option
Your subscribers must be able to easily opt-out (or unsubscribe) from your messages. You have to give this option to your subscribers in every message you send. At the bottom of the email, you can provide a link to unsubscribe….6. Honor opt-outs quickly
If a subscriber wants off your list, you have 10 days to do it. You can’t charge any fees for this service, ask for any personal information, or sell the person’s contact information to another company. Most email service providers will manage this process for you …7. Monitor what others do for you
If you hire another company to manage your email list, you will still be held responsible if the company breaks any of these rules.If you’d like more information, The Federal Trade Commission offers a compliance guide on its site to help small businesses comply with the CAN-SPAM Act.