Other increasingly popular forms of voice-recognition services include Apple's Siri assistant on mobile devices, Microsoft's Cortana and the "OK Google" feature for speaking to Google's search engine. Spoken commands can also be used to find something to watch on some TVs, and an upcoming Barbie doll will include an Internet-connected microphone to hear what's being said.
These innovations will confront people with a choice pitting convenience against privacy as they decide whether to open another digital peephole into their lives for a growing number of devices equipped with Internet-connected microphones and cameras.
The phenomenon, dubbed the "Internet of Things," promises to usher in an era of automated homes outfitted with locks, lights, thermostats, entertainment systems and servants such as the Echo that respond to spoken words.
It's also raising the specter of Internet-connected microphones being secretly used as a wiretap, either by a company providing a digital service, government officials with court orders or intruders that seize control of the equipment.
"We are on the trajectory of a future filled with voice-assisted apps and voice-assisted devices," Forrester Research analyst Fatemeh Khatibloo says. "This is going to require finding the fine balance between creating a really great user experience and something that's creepy."