Hopper

Hoppers  are blocks that will be added in Update 0.14.0. They are used to catch items, or to transfer items into and out of containers such as Chests.

Crafting

 * 5 Iron Ingots + 1 Chest => 1 Hopper

Uses
Hoppers are mainly used as a method of transfering items from one container to another, and to catch any item entities that fall on it.

Interaction
Hoppers interact with different containers in different ways:

Chests
Any Hopper attached to a chest with push an item from its own inventory into the chest. If a chest is above the hopper, it will pull the item from the chest into its own inventory.

Furnaces
A Hopper attached above a furnace fill fill the furnace's ingredient slot. A Hopper next to a furnace will only fill the fuel slot. Also, a hopper below a furnace will only collect items from the output slot.

Brewing Stands
A Hopper above a brewing stand will only fill the top ingredient slot and will only push potion ingredients into that slot. A Hopper to the side of a brewing stand will only push water bottles and potions into the bottom three bottle slots, and Hoppers below the stand will collect any resultant potions.

Dispensers
Hoppers can fill and remove blocks from Dispensers.

Trivia

 * Hoppers can be used for automation, as well as in transporting of items over long distances.
 * Hoppers will not function if a Redstone power source (like Redstone Torch) is placed adjacent to it.