It's definitely possible, but the limit is 18,446,744,073,709,551,616 rows, or 281 terabytes, whichever the database hits first, so you probably could put the discussion off until year 2 or 3 if you really had to.
Kind of like maybe the 'Send your friends money, divide the restaurant bill easily!' app founders first think will change the world could get really popular if it gets on the frontpage of HN..