But Aanya's care-free attitude dissolved into paranoia a few months ago shortly after her mother bought Amazon's Echo, a digital assistant that can be set up in a home or office to listen for various requests, such as for a song, a sports score, the weather, or even a book to be read aloud.

After using the Internet-connected device for two months, Aanya, 16, started to worry that the Echo was eavesdropping on conversations in her Issaquah, Washington, living room. So she unplugged the device and hid it in a place that her mother, Anjana Agarwal, still hasn't been able to find.

"I guess there is a difference between deciding to share something and having something captured by something that you don't know when it's listening," Agarwal said of her daughter's misgivings.