it looks like it worked for me buying a amazon gift card!!!
I got this from Amex for Zappos.com and amazon.com!!!
"Thank You for using your Synced Card!"
Dear: ***** ********
Thank you for using your synced American Express® Card
ending in 51000 at AMAZON.COM LLC!
Get more savings, rewards, and experiences you'll love by visiting
Amex Sync with Facebook here!