The only way for people to trust you is to build a relationship with you, or your products. The better you are able to communicate with your fans and update you fan base, the more likely they will spread via word of mouth what you want them to spread.
If you have an email list where you can contact your list and follow up regularly you can create a lot of value and personalized relationships that will help you see your fans and get interaction with them about what they want. What there desires are and how you can help them.
Delivering value to your fans will help them engage you in many more ways than one.
Here is what I am personally doing right now in my business: Sending out personal emails full of value to get people thinking about what they want out of life. If you don’t know what you want, you won’t ever get what you want.
Any blog post I ever write, I can email my list and send them straight there. You definitely want email lists to be able to communicate with your list so they can be informed of anything new and exciting you have coming up in your universe.