I noticed that the end opposite of the HDMI seemed to have a micro USB in port on it. I suspect that it is powered via that, however none of the demonstrations showed it being plugged in, so I believe it may have an internal battery which needs recharging.

Edit: The specs at the bottom of the page don't list a battery but it does list an included power adapter, so I guess you have to have that plugged in at all times.

Edit 2: Certain versions[1] of the HDMI spec provide power. It's possible that the USB is a backup solution for older spec'd TVs.

[1] http://en.wikipedia.org/wiki/Mobile_High-Definition_Link#Fea...

You sure it's not just for firmware updates? The GameStick (http://gamestick.tv) is powered purely via HDMI.

The Gamestick is powered by MHL if you have it, but you have to power it through its micro-usb port if you have normal HDMI (source: have one). I expect it's the same for the Chromecast.

In the "What's in the box" they list a "USB power cable" and "power adapter".

Yeah, the video in the carousel has a brief fine print message that says the "power adapter is required (not shown). "

Opening it on my phone said "We are out of inventory. Check back soon.". Opening on PC said "Coming soon" and a refresh of the page let me buy it. Hope that helps.

Now it's saying "coming soon".