There is a twitch promotion allowing you to get Purple Footprints EffectPurple Footprints EffectBoots Modifier
Stack Size: 20Adds purple footprints to a pair of boots.Right click this item then left click some boots to apply it., Purple Weapon EffectPurple Weapon EffectWeapon Effect
Stack Size: 20Adds a Purple effect to a weapon.Right click this item then left click a weapon to apply it. and Purple Portal EffectPurple Portal EffectPortal ModificationThis character's portals use a purple effect.Right click this to set or remove your Portal effect. if you have twitch prime.
Acts divide up the game into sections. Each major release adds a new act. GGG intends to have 10 acts in the game . Each act takes about 12 months to complete depending on available development resources 
- Paul Younger (October 21, 2013). "Path of Exile Interview with Grinding Gear Games CEO Chris Wilson". PC Invasion. Retrieved June 23, 2016.