Once a futuristic luxury, internet-connected home cameras have become reasonably common — and relatively cheap. Around 33 million American households — 27% — now use the cameras, according to an estimate from Parks Associates, a consumer technology market research firm.

For consumers, the benefit is clear: Constant or near-constant surveillance that can catch burglars in the act and provide clarity on anything that happens outside their homes. But with these systems almost always relying on cloud-based storage and analysis, many technologists have noted that they are ripe for abuse, particularly as they become more complicated and attached to increasingly advanced analysis systems.

In Guthrie’s case, it appears that even without the requisite subscription plan to have the Nest camera fully operational, it did record and transmit video of someone coming to her door the morning of her disappearance.

From the article, "One nation, on camera: Internet-connected doorbells promise security but raise privacy alarms" by Kevin Collier