American Express and Amazon are teaming up to give AMEX cardholders an early Christmas present (or, insert name of your preferred holiday here). Spend $75 at Amazon on your synced AMEX card and you’ll receive a $25 statement credit.
You need to sync an AMEX card with Twitter before you register for the offer. I just did it, took all of about 30 seconds. Then, another 30 seconds to send out the Tweet to #AmexAmazon and receive a reply, and I’m all set!
The only particularly relevant terms are that you need to sync your AMEX card with Twitter and spend $75 cumulatively between now and December 31, 2013 (you can accrue the $75 in multiple purchases).