E-Mail-Kommunikation ist persönlich!

"All email communication will be of value and personal to every customer." This is a strong statement, but not an unrealistic one.
Email should contain content and a message that piques the interest and engagement of your customer. When you communicate with your customers, remember that your communication is a representation of your business and your brand. What's more, the inbox is an important part of your customer's life, a very personal place that should be treated as such.
As well as providing value, you also need to be consistent across all communication. If your messages are not coordinated across all channels (email, Facebook, Twitter), then your customer may have an imbalanced experience with your brand.