If I add someone to a list in Klaviyo, are they added to a list in Mailchimp? What about if I add someone to a list in Mailchimp, are they added to a list in Klaviyo?
No, if you add someone to a list in Klaviyo they will not be added to Mailchimp. However, if you add someone in Mailchimp, they will be added in Klaviyo after 30 minutes if the address has status “subscribed” or "unsubscribed.” If the email address in Mailchimp is in status “pending” (added with double opt-in, but has not yet confirmed their subscription) or “cleaned” (the address bounced and was removed from the list), they will not be synced to Klaviyo. When an address confirms their subscription, they will move from “pending” to “subscribed” in Mailchimp and will be synced to Klaviyo in the next periodic sync.
Additionally, any signup form that is built into the theme will need to be redirected to Klaviyo or swapped out for a Klaviyo form.