David Sarno:

The app, which will be released as a downloadable “over the air” update, is available only to Sprint wireless customers — and of those, only owners of the Sprint Nexus S 4G smartphone.

and later:

The other problem is that NFC-enabled credit card terminals are still relatively rare — though they are now deployed at hundreds of thousands of locations, credit card giants like Visa and MasterCard have tens of millions of locations worldwide.

Not a good way to get a service going: offer it only to a very select few, in select locations — neither of which may actually overlap.

Posted by Ben Brooks