Expanding their Twitter integration, AmEx is now letting Sync program participants buy goods via Twitter with only a hashtag. Deals are rolled out, the first being a $25 AmEx gift card for $15, customers can purchase by tweeting the appropriate hashtag – in this case #BuyAmexGiftCard25. A verification is sent, your card is charged, and your purchase arrives in 2-days for free. Previously, cardholders could receive hashtag based discounts. More here.