I went to the London Minfo Design Hackathon, met bunch of talented people and worked on this concept. Minfo is a platform that allows you to have more information related to things around you. Imagine you're waiting for the bus and a digital board next to you are shown an advertising about some product that you like. Instead of taking pictures or trying to remember the name or web address, you just tap to absorb and the app look for inaudible sound that has been embedded in the advertising.
Find the live prototype link at the end and feel free to play with the prototype.