Many of my friends hit level 60 without ever knowing this option existed, I really hope Blizzard makes elective mode the default in the future. For example a Monk could choose Serenity (An invincability shield) and Breath of Heaven (A healing spell) two defensive skills at once.
By default you are only allowed to pick one skill from each category at a time, but if you turn on elective mode you can pick as many skills from any category as you would like. Basically Diablo 3 skills are broken down into 7 categories such as Primary and Defensive. Elective Mode improves the game so substantially that it completely baffles me why Blizzard decided to hide this option in the menus.
