Alba by Stack is a light bulb that knows the time of day, how many people are in the room, and how bright it is, and adjusts itself accordingly in an intelligent, easy-to-control manner. Startup Battlefield final round judges: Roelof Botha (Sequoia Capital), David Lee (SV Angel), John Lilly (Greylock Partners), Marissa Mayer (Yahoo), Keith Rabois (Khosla Ventures), Kevin Rose (Google Ventures).