No. A widget is basically a dynamically updating screen on your desktop, that hooks into an existing app.
Ie. A favorites widget would list your favorites on your desktop, allowing you to scroll through them,on your desktop, and let you either call, email or text them, directly from the desktop.
As you add or remove favorites in your address book, those changes will be reflected in the widget.
Same with calendar appointments , todo lists etc.
So, you can at a glance, without doing anything see your upcoming appointments, and list of todos.
You can also see not only who messages you, but you can see the message as well.