Remember when Lady Gaga pinged smartphones and presumably alarmed dogs by transmitting inaudible, high-frequency audio at a concert with Sonic Notify tech? It turns out Apple's applying for a patent to do something similar, namely "audio hyperlinking" that can be contained within an audio stream. Cupertino's application says that such sound waves could be audible or outside the normal hearing range of 20Hz to 20KHz and "cause an effect in the user interface" of a receiving device. That could be useful during a podcast, for instance, to give users links to articles relevant to a discussion via sound waves alone. The application goes on to describe how such data could be encoded into an audio stream and read by the receiving device, and leaves wiggle room for a wide range of uses. Call us cynical, but we imagine that includes a way of sneaking in more ads.