Do you write a company newsletter?  Worried about your domain getting blacklisted as a spammer?  What can you do to avoid this?
There is a laundry list of things that you should do to avoid being classified as spam.  These things will all help you, but may not give you an absolute guarantee that someone won’t hit a spam button on your email – anyone is free to do this.
1. Make sure your list of people is permissions based.  Do you have permission from the individual to send them emails?  Are they receiving emails because they opted in as interested parties or have done business with you?
2. For your sign-up list, utilize double opt-in authentication.  For example, when someone signs up on your page, they then have to receive an email to confirm membership in the list to receive emails.  Various plugins for WordPress let you utilize a system like this, for instance, the plugin called “Newsletter”: http://www.satollo.net/plugins/newsletter
3. Structure your message so it does not look like a spam email:
– Don’t use links with IP addresses in them, make sure they are fully qualified domain name URLs
– Add in a message in the header to the effect of…”You are receiving this message because you have done business with, are an interested party in,…signed up with…. To unsubscribe,…..”
– Make sure the email is written well / proper grammar – as if you were writing a letter
4. Stagger the delivery so as not to send out a ton of email in one hour – find out the limit with the hosting provider you are using to send the mails
5. Monitor the status of your domain using mxtoolbox.com to check for any potential blacklisting of your domain
6. Unsubscribe anyone who requests it right away, and anyone whose email address bounces
7. Make sure the email address you are sending from is a valid email address
8. Put in language at the bottom again about unsubscribe options and your company privacy policy
9. Take a look at how to avoid being classified as spam with a spam service such as Spam Assassin, they will provide you with a set of rules in addition to the ones I have listed above: