SilverPush is an Indian startup that's trying to figure out all the different computing devices you own. It embeds inaudible sounds into the webpages you read and the television commercials you watch. Software secretly embedded in your computers, tablets, and smartphones picks up the signals, and then uses cookies to transmit that information back to SilverPush. The result is that the company can track you across your different devices. It can correlate the television commercials you watch with the web searches you make. It can link the things you do on your tablet with the things you do on your work computer.
Your computerized things are talking about you behind your back, and for the most part you can't stop them -- or even learn what they're saying.
This isn't new, but it's getting worse.