Communication is a two way street. Your supporters are going to engage with you and let you know what they care about. Analyze your email stats and social media engagement to learn what's most important to them.
You'll find email stats under Communication > [Broadcaster name] > Email. Locate the sent email blast. Hover over the blast and click Edit next to the email blast or click on the slug. Stats will appear in the Dashboard section of your email blast.
You can click on "opened" to see a list of all the people who opened the email. From here you could add them to a list of folks who regularly engage with your nation or who care specifically about the subject of the email.
Visit People > Filters to search for who has opened an email from a specific broadcaster in a certain amount of days or just opened a particular email blast.