the buyer pays taxes,for USA and some cases , Australia,EtSY collects the taxes and remit to the tax authority.
For most foreign countries,customs duty is collected by the local post office when they deliver the package to your buyer.
etsy has its own global shipping,similar to Ebay,I dont think so,I have not seen any,But I know it collects tax for Australia if it is under a certain amount,whether you use global service or seller ships himself.
You may want to ask on ETSY column