It's the electronic equivalent of passing notes without lifting a finger. The Chirp app by Animal Systems promotes near-passive communication, sending and receiving links, images, and notes through the exchange of a synthesizer tone.
Download and launch the app, then play this video to experience the process:
(may require re-loading the page)
Transmission only works when others around you run the app (and it only runs when open, not from the background). What fun is "sonification" if there's no one there to hear?
Unlike other methods of passing electronic content, playing the Chirp file is a single push-button process, obviating the need for the clunky process of scanning a QR code. Receiving the file is automatic when you have the app open. While I can see similarities with electronic business-card site Bump, but one advantage to Chirp being that you can share information passively, regardless of whether you know the recipient. And you can send Chirps asynchronously via twitter, facebook, or email.
The app had journalists buzzing at London Fashion Week, since retailer Topshop launched a marketing campaign based on embedded chirps "to let the clothes speak for themselves."
The developers are promising PC-based and other hardware support for the applications will be forthcoming. There is an Android version of Chirp, but is it really necessary? Android's support for near-field communication means that many of the same features could be accomplished soundlessly, via pass over NFC-enabled stickers. But, for iOS devotees, sharing on the fly, and transfer between platforms, Chirp has terrific potential.