In 2013, investors said we were crazy for creating a business around a smart doorbell. The Internet of Things (IoT) was still nascent and only a few startups (Nest, Dropcam and SmartThings) were starting to create real traction. Yet we believed in the dream of the "smart home" and continued creating the future we wanted to see.

Fast forward five years and IoT is now mainstream. Nest's smart thermostat put IoT on the map and Amazon's Echo product and Alexa voice assistant accelerated the industry forward by giving consumers a new user interface (voice) and endless user experiences. Google Home's entrance and the addition of hundreds of major brands and corporations have propelled the industry up the adoption curve, heading into the "early majority."

2019 should see continued expansion as the IoT industry pushes from the smart home into smart everything. Diversification across industries and increasingly intelligent applications will lead to deeper and wider penetration.

Here's a look at what you can expect in 2019 in the Internet of Things industry.