re: #6 Spocomptonite

They probably don’t need to do much complicated voodoo for Washington sales, just check the billing address, add the sales tax, and send it to the state.

The issue is that they’d have to charge sales tax for a person in Vermont who is buying an item through Amazon (based in WA) via a California affiliate.

That gets confusing (possibly annoying) for the customer, who is used to not paying sales tax on Amazon purchases, and it means more infrastructure at Amazon devoted to tax issues.