Best Practices for Bulk Emailing
Many email providers, like Gmail, have certain requirements for bulk emails. Here are some best practices when sending emails to lots of people from your program.
Authenticate Your Emails
Recipients shouldn't need to worry about the intricacies of email security standards, but they should be able to rely on an email's source. If you send bulk emails, you should authenticate your emails. This helps protect your email domain against spoofing, and helps prevent your outgoing messages from being marked as spam. To do this, set up DKIM (DomainKeys Identified Mail). If you use Gmail, check out this Google Support article for more information: Help prevent spoofing and spam with DKIM.
Enable Easy Unsubscription
Recipients shouldn't have to jump through hoops to stop receiving unwanted messages. It should take one click. If you send bulk emails, you should give recipients a way to unsubscribe in one click. For example, you might include a note at the bottom of every email with an "Unsubscribe" link that notifies you with the person's email address when they click it. And you should honor these requests! Don't send bulk emails to people who have asked you not to.
Ensure You're Sending Wanted Emails
Nobody likes spam emails, and many email providers already have tools that keep out unwanted messages. In fact, Gmail enforces a spam rate threshold that bulk emailers must stay under. If you send bulk emails, you should ensure that your recipients actually want the message sent to them. If too many people mark your emails as spam (or if your email provider thinks your emails look like spam), your recipients may not receive the message. Best rule of thumb: Send informative emails that people want to see.