Doc Rivers has received a promotion from the LA Clippers. Previously, in addition to his head coaching duties, Doc was Sr. VP of Basketball Operations. His new title, President of Basketball Operations. As far as the difference in his job duties, not much. This is more of an organizational restructuring.
Rivers becomes the fourth president/coaches in the NBA right now, along with Spurs Gregg Popovich, Pistons Stan Van Gundy and Timberwolves Flip Saunders.