TVs may not track yet, but phones or PCs are already tracking the TV ads people are watching:<p>&quot;Beware of ads that use inaudible sound to link your phone, TV, tablet, and PC. Privacy advocates warn feds about surreptitious cross-device tracking.&quot;<p><a href="http:&#x2F;&#x2F;arstechnica.com&#x2F;tech-policy&#x2F;2015&#x2F;11&#x2F;beware-of-ads-that-use-inaudible-sound-to-link-your-phone-tv-tablet-and-pc&#x2F;" rel="nofollow">http:&#x2F;&#x2F;arstechnica.com&#x2F;tech-policy&#x2F;2015&#x2F;11&#x2F;beware-of-ads-tha...</a>