Amazon Echo is apparently always ready, always listening and always getting smarter. So goes the spiel about the sleek, black, voice-controlled speaker, Amazon’s bestselling product over Christmas, with millions now sold worldwide. The problem is that when you have Alexa, the intelligent assistant that powers Amazon Echo, entering millions of homes to do the shopping, answer questions, play music, report the weather and control the thermostat, there are bound to be glitches.

And so to Dallas, Texas, where a six-year-old girl made the mistake of asking Alexa: “Can you play dollhouse with me and get me a dollhouse?” Alexa promptly complied by ordering a $170 (£140) KidKraft doll’s house and, for reasons known only to the virtual assistant, four pounds of sugar cookies. The snafu snowballed when a San Diego TV station reported the story, using the “wake word” Alexa, which is the Amazon Echo equivalent of saying Candyman five times into the mirror. Several viewers called the station to complain that their own Alexa had woken up and ordered more doll’s houses in what turned into a thoroughly 21st-century comedy of consumer errors. And a bonanza day for KidKraft.

Many of Amazon Echo’s gaffes stem from misunderstandings arising from an intelligent assistant who never sleeps (and an owner who hasn’t pin-protected their device). Last March, NPR ran a story on Amazon Echo’s capacity to extend the power of the internet into people’s homes. Again, Alexa took its power too literally and hijacked listeners’ thermostats. Another owner reported how their child’s demand for a game called Digger Digger was misheard as a request for porn.

On Twitter, Amazon Echo owners continue to share items that unexpectedly end up on shopping lists, whether sneakily added by children or simply because Alexa misheard or picked up random background noise. One owner uploaded a video in which their Amazon Echo read back a shopping list that included “hunk of poo, big fart, girlfriend, [and] Dove soap”. Another included “150,000 bottles of shampoo” and “sled dogs”.

Behind all this lies the more serious question of privacy: what happens to the data collected by voice-activated devices such as Amazon Echo and Google Home, and who is able to access it? Most recently, US police investigating the case of an Arkansas man, James Bates, charged with murder, obtained a warrant to receive data from his Amazon Echo. Although Amazon refused to share information sent by the Echo to its servers, the police said a detective was able to extract data from the device itself.

The case not only puts Alexa in the futuristic position of being a potential key witness to a murder, it also raises concerns about the impact of letting a sophisticated virtual assistant – a market estimated to be worth $3.6bn by 2020 – into our homes. As Megan Neitzel, the mother of the girl who wished for a doll’s house, put it: “I feel like whispering in the kitchen … I [now] tell my kids Alexa is a very good listener.”