As Steven said that there are a lot of sensors, Fitbit, Jawbone up but I cannot think about actuators. I tried to think about any wearable actuator link to sensors, Fitbit or Jawbone. They just present statics and using vibrator. It is sometimes helpful but not a best way to inform to people. Last 1 year ago, when I was in graduated student in Korea. My Thesis projects is researching casual information visualization.(http://chanwookmin.com/works/casual-information-visualization-system/) The thesis is about what data is helpful for people in their daily life and how to present to people. To be specific, I focus on people’e sitting habit when they are using computer. I tracked people sitting posture using chair with pressure sensor and it visualize unique way. For example, I changed mouse pointer. when people lean left, mouse pointer point to left(Mouse pointer’s shape is arrow. This is because it can be present people posture.). Moreover if they stay bad sitting posture, mouse pointer is getting bigger. This is also stressful but I think it is good way to change habit because it is hard to recognize their habit. In my case, The good actuator is that keep notifying to people, realize their problem and they try to change their action even though it is stressful.