There are plenty of task reminder apps available on the market. The Droplet happens to be a wireless button that brings a physical aspect to the process, helping you get things done when you need to. You can attach the button to anything. When you are done, just push the button. The companion app provides you with a reminder when you have forgotten to complete a task.
By having a physical button to touch after you have completed a task, you are going to have a difficult time forgetting to get things done. The companion app lets you track your progress. The Droplet hub lets you use multiple buttons. The app runs on iOS/Android devices. You can find out more about the Droplet on Kickstarter.