Disclaimer: I suppose this is news because it happened recently. However, I strongly disapprove of this practice as it defaces tombstones. Depending upon the adhesive used, attaching anything to a tombstone also can actually accelerate the tombstone's decay. When discussing historic tombstones, most tombstone scholars would be aghast at the idea of using adhesives or any other means to attach a new object to an existing tombstone.
Quoting from an article in the BBC News web site:
"A son has fitted a barcode on his war hero father's gravestone in Bridgend so that visitors can learn about his life. The QR (quick response) code can be scanned using smart phones to access a webpage about Charles Davies. The former merchant seaman, who died last year aged 91, took part in the Arctic convoys during WW2.
"Known as the 'journey to hell', more than 3,000 men died on the convoys which took supplies to the Soviet Union from 1941 to 1945. Joe Davies said he hit upon the idea for the barcode through his IT job using QR codes in public parks to tell people more about the plants and trees."
You can read the entire BBC article at http://www.bbc.co.uk/news/uk-wales-south-east-wales-25576682.
Before you run out and deface a loved one's tombstone, I suggest you also read my article from last May at http://goo.gl/UEufH0.
You will note that I advocate using a SEPARATE marker containing a QR code to be placed adjacent to, but not attached to, the tombstone.