Credit-card holders post a specific hashtag on Twitter to trigger payments from their accounts. Products from Amazon, Sony and Microsoft are being offered at a discount to entice shoppers to use the new service.
However, one retail expert dismissed the initiative as a "gimmick" that was unlikely to catch on. This is not Amex's first tie-up with social media.
It already operates a voucher-free discount scheme with Foursquare - a location-based network - in the UK and US. It has also offered savings to users who tweet promoted hashtags - such as #AmexWarby - listed on its Twitter account.
An Amex spokesman was unable to provide any detail of when it might extend the latest scheme to other countries.
Source: BBC News
