The many meanings of opt-in
An email address was entered into our website
An email address was associated with a purchase on our website.
We have a relationship with a 3rd party that shares email addresses with us.
We have a cookie on a web browser that visited out website and we sent an email to the address associated with that cookie.
We both went to the same conference and the attendee list was given to every exhibitor.
One of our employees has a connection with this person on LinkedIn.
They liked our Facebook page.
They commented on our Instagram feed.
They followed us on Twitter.
We have a legitimate interest under GDPR to send you email about our products.
The email address is published on a website as a contact point.