When this goes through (though possibly not this year) some business is going to make a mint providing a back-end service to know how much taxes need to be applied towards a purchase. Amazon/PayPal/Google Checkout should start building that now, if they haven’t already.
PayPal has to be one of the worst payment processors for business it seems on the internet.
That’s a ginormous difference in fees, especially for the complaint of not knowing anything about anything.
What more do you need to know?