From the Super Mario Wiki
Candy Areas, called ? Candy in the Mario Party 8 instruction guide, are areas that appear on the boards of Mario Party 8. They are essentially the successors of the Orb Spaces from Mario Party 6 and Mario Party 7. Whenever a player passes over a Candy Area, they will receive a free Candy at random. Candy Areas are not counted as actual spaces, since they're impossible to actually land on.