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.
SilverPush’s ultrasonic cross-device tracking was publicly reported as long ago as July 2014. More recently, the company received a new round of publicity when it obtained $1.25 million in venture capital. The CDT letter appears to be the first time the privacy-invading potential of the company’s product has been discussed in detail. SilverPush officials didn’t respond to e-mail seeking comment for this article.
Android apps are more likely than iOS apps to share with a third party personally identifying information such as name (73% of Android apps vs. 16% of iOS apps) and email address (73% vs. 16%). For location data, including geo-coordinates, more iOS apps (47%) than Android apps (33%) share that data with a third party.