I wanted to check if there was a way to manage subscription lists opt-ins and opt-outs based on the Contact Id/Lead Id and not the email (or the combination of Contact Id and e-mail)?
Also we have at least 13 different subscription lists/topics. What is the best way to manage subscriptions to those? Is the best way to add custom fields (corresponding to each subscription list) to the Contact and Lead entities and use a work flow to update the preferences? Or is there a different way?