To evaluate the success of self-service initiatives in terms of user adoption and engagement, a holistic view of various metrics is essential. Monitoring the number of articles viewed or downloaded gives an indication of user engagement with content. The percentage of cases deflected through self-service channels highlights the effectiveness in resolving issues without live agent support. Customer satisfaction ratings provide direct feedback on the user experience. Thus, 'D. All of the above, providing a holistic view of self-service adoption, effectiveness, and user satisfaction' is the most informative measure of success in self-service goals. Reference: Salesforce Service Cloud Metrics