Amex Sync offers $25 off $75 Amazon.com

Update #2: Direct enrollment no longer working. Back to Twitter.

Update: no Twitter required, just go to this link and register all your cards!

This is one of the most generous Amex Sync promos I've seen.  Just sync your credit card with Twitter, and then tweet #AmexAmazon.  For more detailed step-by-step instructions, see this post. You'll then get a $25 statement credit for each $75 purchase.  Once confirmed (wait for a reply via Twitter from @AmexSync), you'll have until December 31 to get your 33% off Amazon.  Sync it fast because there are limited quantities of these promos.  Amazon gift cards purchases counted for me, but you might want to check the latest Slickdeals thread to confirm that before buying.