The Model is simply your business or data layer. It's completely UI independent.So when you develop for example a WPF application,
and you would like to switch it to a silverlight application later on, you can just re-use your Model.
Your ViewModel exposes the data to your View. So it's 'custom' build to show the data for your View,
even though your ViewModel acts independently from your View, and your View is developed independently from the ViewModel.
So they are in a way 'connected'.
Your view just connects to the data with databindings. They can be one way bindings (property to source or the opposite) or two
way binding. I'll give examples of that later on, basically it means that if you change something on the screen, if it gets
changed in your properties too, or only your property/screen changes.