SAN FRANCISCO (AP) — Like a lot of teenagers, Aanya Nigam reflexively shares her whereabouts, activities and thoughts on Twitter, Instagram and other social networks without a qualm.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.