There are two things we can improve if we'd like to scale this application. The first one is passing event handlers to a child component and listening for the child to fire back with data. That itself may work well for such a small example but, in real life, it can become very difficult to track down such a workflow. The child can be a grandchild or even further down the tree, and we have to pass that prop event through all of them, even if they don't need it. To solve this, we can implement a different approach. A child who needs to fire an event back with the data (props) to the parent; we can dispatch an action to a common function that can modify the data on the top level above the parent and pass the data down again. You can say that we are doing something like that by calling the Meteor Methods from the Parent, and the reactive container will pass the props down again. This is pretty close, but we can do better. This need of a child to parent data passing...