Email is a great channel for promoting your content, however with GDPR in place, make sure that you provide your audience with the option to opt-out.
An ‘unsubscribe’ button should be clearly presented in your email and should direct readers to an easy and quick way to unsubscribe. Have a clear sign-up field on your website should people want to re-subscribe in the future.
The number one reason why you should give people the ability to opt out is to avoid spam complaints.
To avoid becoming an accidental spammer, never email someone you don't have permission to contact.