Guinness QR code puts a little more magic into sipping the black nectar

Empty . . . it's just an ordinary beer glass. Fill it with a pint of lager . . . and it's still an ordinary beer glass.

But fill it with dark Guinness and, abracadabra, it leaps to life - displaying a QR code.

You then Scan the code with your smartphone, and it "tweets about your pint, updates your Facebook status, checks you in via Foursquare, downloads coupons and promotions, invites your friends to join you, and even launches exclusive Guinness content," Adweek tells us.

All that, before you have even had a sip!

The inspiration comes from BBDO New York.

Even better, The Guinness code works round the clock, unlike the QR code from a Korean retailer which is sunlight-activated and scannable only at lunch, when the shadows line up.