Did you know that the first IoT murder was supposed to happen in 2014? Don't believe me, check out: First IoT-mediated murder could occur in 2014, experts warn http://www.itpro.co.uk/hacking/23242/first-iot-mediated-murder-could-occur-in-2014-experts-warn.
Security is a very important part of IoT, be it as simple as stealing data or monitoring your door sensor to know when you have left your home or spoofing a data record to indicate an unwanted event to create havoc. Security is essential.
Now we need to invest in a firewall for our toaster.
IoT devices are being used to perform DDoS attacks on other entities. Stealing data from a sensor is one thing, but reprogramming/hacking a smart device to think it is something else is a new level of disaster.