From the API Doc:
"Note that <OptInSource> element is required, and must be ACTION_BY_CUSTOMER for any contact list that was not included in a sign up form. In other words, if the user is subscribing to a list, you can use ACTION_BY_CONTACT, but if the account owner is adding a user on his or her behalf through this API, then you must use ACTION_BY_CUSTOMER. Setting the Opt In Source to ACTION_BY_CONTACT will trigger any applicable emails to go out to the contact, such as welcome emails or change of interest emails. Setting the Opt In Source to ACTION_BY_CUSTOMER will suppress those emails, but will still trigger Autoresponder emails, if applicable (please note that autoresponder emails are only triggered for contacts that are not on any existing lists at the time that they are added to a list that is set to receive autoresponders)"
Question: Does this mean we can have a Facebook connect on our website. We get the email from the user. Call constant contact API and add the email to a email list. User receive welcome email (and future scheduled emails) WITHOUT they have to confirm the email first?
If you put a signup form directly on your website or facebook, and the contact themselves are adding themself, then you can set the opt in source to "ACTION_BY_CONTACT" and they will receive a welcome email.
If you are adding the contact as a Constant Contact site owner, you should use action by customer. That will not trigger the welcome email, but it will put the contact in your contact list and send any autoresponders that are set to go out to the list that they were added to. To summarize:
action by customer: get autoresponders, get put into list(s)
action by contact: get autoresponders, get put into list(s), get welcome email
This is all assuming that you don't have confirmed opt-in set to ON. It is off by default, but some customers choose to turn it on to make all of their contacts confirm their subscription before getting put into a list. Let me know if you need any further clarification.
API Support Specialist