What does "Most Active Teammate" mean?
Most Active Teammate is a system standard field that shows as a header field for people and organizations. It is determined by the teammate that is associated with the most Messages, Incidents (if there's an active Help Desk integration), and Notes for the contact within the three months before Last Contact. Currently, it does not consider the number of Documents associated with teammates.
Last Contact is another system standard field that is the date of the latest Message, Incident (if there's an active Help Desk integration), or Note.