usually .
refers to the preceding object and allow you to point to the sub properties, you may consider it as a separator as well. as mentioned in the question there is no preceding object so in this case the .
refers to the DataContext itself and so Binding="{Binding Path=DataBinded}"
and Binding="{Binding Path=.DataBinded}"
are equal
you may consider the following example when you want to bind some text value directly
<TextBlock Text="{Binding}" />
or
<TextBlock Text="{Binding Path=.}" />
both of the example above points to the DataContext of the TextBlock and will bind to the same.