Email deliverability for mass emails is a complicated art, and one that NationBuilder takes very seriously. There are a couple of big things you can do to make sure folks are getting your emails:

One: Use email addresses that match a custom domain. Emails from "Joe Blue for Congress" for your nation joeblueforcongress.com should not come from "joeblueforcongress@gmail.com." Take the time to make sure you're set up with a good custom domain name and custom email addresses before you start using blast email services.

• Here's the basic info for setting up a custom domain with NationBuilder; and
• Here's how to link up 10 free custom Gmail addresses to your nation;

Two: Use NationBuilder's two email profiles wisely. The first is "Supporters" and includes people who've opted in to receiving communications from you. The second is "Prospects" and should be used for first-time mailings to voters and personal contacts who are hearing about your nation for the first time. These two email profiles should never be used interchangeably.

For more information on email deliverability, you can subscribe to Deliverability.com's blog here.