This past week, Insteon, the home automation device maker announced that their line of smart light controllers can be controlled with the Amazon Echo. So the command "Alexa, dim the living room lights to 50 percent" will dim the living room lights.

'Alexa, hit the lights': Amazon Echo adds Insteon support - CNET

Then today, Phillips announced that their wi-fi enabled LED bulbs will now take commands from Apple's Siri via HomeKit from Apple.

Talk to Your Philips Hue Lights Via Siri | News & Opinion | PCMag.com

I wonder what Cortana will do for us.