It's best to describe this as "confirmed opt-in". The term "double opt-in" can also be used by marketers to describe them having received your email twice. Usin

It's best to describe this as "confirmed opt-in". The term "double opt-in" can also be used by marketers to describe them having received your email twice. Using "confirmed opt-in" is unambiguous. "Double" could mean anything, and in any case registration and confirmation are two separate steps of a single opt-in. I'm surprised to see Mailchimp using the "double" term. See: http://en.wikipedia.org/wiki/Opt-in_email http://en.wikipedia.org/wiki/Opt-in_email "The term double opt-in has also been co-opted by spammers, diluting its value."