The memorandum continues: “As a result, if a seller uses convertible virtual currency as consideration for goods or services, sales tax is due based on the amount allowed in exchange for the virtual currency. If the customer that provides convertible virtual currency in the trade receives property that is subject to tax, the customer owes tax based on the market value of the virtual currency at the time of the transaction, converted to U.S. dollars.”
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I don't think it changes anything from BTC-accepting retailer point of view. It's just they treat customers who pay with bitcoins as 'sellers'.
I don't know much about US tax rules, but don't think customers who use bitcoins from time to time will be liable to pay such tax.
It's basically like selling something to the pawn shop.
The question is whether retailers will be expected to collect personal info from bitcoin-paying clients etc.