What can I do with RaisePropertyChanged?

I am using MVVM Light in a Silverlight application for Windows Phone.

I really don't understand how RaisePropertyChanged works; Let me explain in code like this

private Recipe _selectedRecipe;

public Recipe SelectedRecipe
{
    get
    {
        return this._selectedRecipe;
    }
    set
    {
        this._selectedRecipe = value;
        RaisePropertyChanged("SelectedRecipe");
    }
}

What should happen when RaisePropertyChanged ("SelectedRecipe") is called?

I expect that a call to a new method with my code will be executed or something like that, but I cannot find something like this in the (several) examples that I found. So how does it work?