Tom Kerber, a director overseeing Internet-of-things strategy for Parks Associates, said sales for video doorbells have grown dramatically in recent years because of the popularity of online shopping.

The last item that Nest announced was a security system made up of three products called Nest Guard, Nest Tag and Nest Detect that will start at $499 and become available in November.

Nest Guard is a portable motion sensor that goes into a main room or hallway and arms or disarms the system. It has an alarm that sounds if an intruder comes into the home and will alert a user to a potential break-in through an app. Nest Detect devices are placed near doors and windows to track when they are open. Nest Tags are small fobs that users can tap on their Nest Guard to turn the alarm off; they can be set to only work during certain hours of the day for a cleaning person, dog walker or other visitor

From the article "Nest announces new hardware products in answer to critics" by Wendy Lee.