I like to think of the problem like this: Imagine building another interface to your app. Take a CLI as an example. Should the 'facebook update' feature be acti

I like to think of the problem like this: Imagine building another interface to your app. Take a CLI as an example. Should the 'facebook update' feature be activated if you use your app through the CLI? If the answer is yes, it belongs to the model. If no, it does not.