it's like 2d barcode to check-in facebook places
let's encode url in audio (like encode signature in image)
and play the audio in the mall or restaurant, to let phones auto check-in to facebook place or google places.

can also do auto checkin with wifi wireless router id, or rfid, etc.

Set WIFI settings according to your location (detected by using CellId or GPS)

Share free public settings on a server, so users of this software will have easy access to wifi internet.