Facilitators are experienced mentors and contributors who lead core mentoring sessions. They coordinate mentors and connect them with participants. Facilitators have access to create new tasks, manage user accounts, and so on.
Mentors are contributors who can occasionally commit a 1- or 2-hour block of time during core mentoring to assist participants. Some mentors participate in core mentoring regularly; others are experienced contributors who are willing to be "backup" when a mentoring session is particularly busy or one of the regular mentors is not available.