Minecraft wiki entry for Development_versions, associated text: Enchantments with negative effects.
Two curses added: the Curse of Binding (Enchantment ID 10) and the Curse of Vanishing (Enchantment ID 71).
Curse of Binding will bind the item to the player, making them unable to drop it or take it off if it is an armor item, although it will drop when they dies. Players in Creative mode are unaffected by this curse.
Curse of Vanishing will make the item disappear if the player dies. /gamerule keepInventory true will prevent this.
Cursed tools, armor and books can be found as loot in some generated structures.