I call bullshit. Run a spectrum analyzer on pretty much any online ad and you'll notice it brick walls at 12-16k. Any sort of compression and you'll never so much as hit 20k, which is the upper end of 'sonic.' You want ultrasonic? Guess what. You're now running at 96k or above because St. Nyquist shits all over you at half your clock speed - your 44.1kHz CD player is only good to 22.05KHz, for example, which is fine because you can't much hear above 18k anyway. Besides which the only people advertisers care about are the 13-25yo kids and their hearing isn't blown out the way everyone over 30's is. You REALLY think your online advertising is using a dog whistle to make your phone and your television work in league against you? Then you're either Andy Rooney or a venture capital firm. Fucking people. Sorry. 6th 16 hour day in a row and I just busted up the rest of my bushmills amongst the crew.
It sounded unbelievable to me, but I did recall reading about it before. I don't remember where, but some Googling brought up this paper: On Covert Acoustical Mesh Networks in Air Just because you're paranoid, don't mean they're not after you? Also, cheers.
Proof of concept and deployment are very different things. Ultrasonic transducers are commonplace, ultrasound-capable speakers are rare, consumer gear capable of hitting those frequencies without heinous harmonics down where you can hear them are a figment of the imagination. It's the equivalent of saying that your smartwatch can beat Deep Blue at chess because after all, they're both computers. Also, cheers. Let's see if this shit works over EDGE. 
Many many years ago, my father decided to take us off-roading in our Laredo after church in the UP of Michigan. Way back into a two rut, we came across a puddle, maybe 20 feet long. My mom tried to talk him out of it, but he went for it. We bottomed out. We spent the next hour jamming branches under the tires in our Sunday best. Ready to go, we climbed in, and the jeep wouldn't start. My brother and my dad then went for help. A long time later, they returned with an old timer that quickly found a loose connection, I think it was the distributor, but I can't recall. We then rolled right out. My mother was not pleased.
I don't watch TV w/ commercials. I guess I'm left out. Too bad, not so sad-
You have to be running an app that uses SilverPush software. This section sums it up pretty well: The user is unaware of the audio beacon, but if a smart device has an app on it that uses the SilverPush software development kit, the software on the app will be listening for the audio beacon and once the beacon is detected, devices are immediately recognized as being used by the same individual. SilverPush states that the company is not listening in the background to all of the noises occurring in proximity to the device. The only factor that hinders the receipt of an audio beacon by a device is distance and there is no way for the user to opt-out of this form of cross-device tracking. SilverPush’s company policy is to not "divulge the names of the apps the technology is embedded," meaning that users have no knowledge of which apps are using this technology and no way to opt-out of this practice. As of April of 2015, SilverPush’s software is used by 67 apps and the company monitors 18 million smartphones.Cross-device tracking can also be performed through the use of ultrasonic inaudible sound beacons. Compared to probabilistic tracking through browser fingerprinting, the use of audio beacons is a more accurate way to track users across devices. The industry leader of cross-device tracking using audio beacons is SilverPush. When a user encounters a SilverPush advertiser on the web, the advertiser drops a cookie on the computer while also playing an ultrasonic audio through the use of the speakers on the computer or device. The inaudible code is recognized and received on the other smart device by the software development kit installed on it. SilverPush also embeds audio beacon signals into TV commercials which are "picked up silently by an app installed on a [device] (unknown to the user)." The audio beacon enables companies like SilverPush to know which ads the user saw, how long the user watched the ad before changing the channel, which kind of smart devices the individual uses, along with other information that adds to the profile of each user that is linked across devices.