Whether you're sending out an email, addressing a postal mailing or otherwise writing to a large group of your customers, you've got to make sure you do it well: clearly, succinctly and appropriately. Understanding how to address a mass customer letter will make communication as a business owner easier and smoother overall.
You may not remember this from high school English, but a salutation is the greeting you use to begin a letter, email, memo or other communication. The traditional salutation is "Dear Mr. or Ms. Last Name." But since you're addressing a group of people, consider broader salutations, like "Dear valued customers." Simply saying "Greetings" is also appropriate for most situations. Be careful with "To whom it may concern." It's impersonal and may create the wrong impression of your brand.
Is your ideal customer casual and low-key? OK with a less formal tone? Then it's probably OK to go with a less formal salutation like "Hey," "Hi" or something seasonal like "Happy spring!" You could be more specific as to how you refer to your customer, as well. For example, if you cater mostly to families, you could address your customers as "Parents" or "Busy moms." Figure out wording that will get your customers' interest and attention right away.
If your business, brand and customer is a bit more formal and traditional, the standard salutation, "Dear customer or customers" works just fine. You can also use specific adjectives, like "loyal customer" or "valued customer."
Depending on the reason for your email, you can punch up your salutation even more. Are you announcing a sale, updating information about special or new products, or just letting your customers know what's new at your business? If so, something that shows the personality of your brand could work well, like "Hello bargain hunters!" or "Welcome to winter, snowbunnies!"
If you're announcing an issue you're experiencing in your business or some other less-happy news, it's not appropriate to make your initial greeting humorous, cute or imbued with personality. In those cases, stick to the basics.
Ensure that you capitalize the first letter of the first word of your salutation, as in "Dear friends." Don't capitalize every first letter of the words in the salutation, as in "Hello Loyal Customers," which is not grammatically correct. Use a comma rather than the business-formal colon after your salutation to create a friendly impression, and make sure it is on a line by itself. Start the body of the letter on the line below the salutation.