Perhaps this is the one time of the year you can predict a large chunk of US consumers will be receiving some additional spending cash - tax rebate time. And many online retailers hope to cash in on customer's stimulus checks, judging from the number of email campaigns and home pages jumping on this trend:
It's a good idea to segment out your non-US subscribers for this type of messaging, even though the sale is extended to everyone. Non-US recipients will probably not understand your offer, and may think they are not eligible.