Setup in three painless steps:Step one: plug the dongle into a free HDMI port and connect the USB power.
Step two: Turn the telly to the correct HDMI source (this may be the last time you're going to do this operation -- bear with me!)
Step three: Go to the URL displayed on your telly, download the Chromecast app. The dongle will invent a passcode which you only need to visually inspect that it's the right one (no entering passwords -- yay!) and you have the chance to rename your dongle to something you like.
Your telly has now become a wireless Youtube- and Netflix- catcher. Run Netflix on your Android device and you'll see a box-with-arcs icon. Click it, and the dongle takes over. If you have a HDMI-CEC compliant television, the teevee will most probably automagically switch to the correct input. Awesome. No plugin or mobile app required. It Just Works&TM;
You can also download a plugin to the Chrome browser, to send browser tabs to your television. Or to the display/projector in the meeting room (which is something we'll probably look at at work some day soon). Sans wires. Nice. The browser plugin is not geographically closed, thank heavens.
The future so brightThere are two things i'm hoping to see next. First, a way to send pictures, from my computer, from my G+ collection or from a "third party" operation like Flickr or my Lightroom. And second, to have Chromecast to act as a display adapter for fairly static and latency-tolerant material. The closest thing we now have is a casting a browser tab, but casting to an external screen would be nice, even if it really is a little outside what i believe to be the Chromecast idea.
Well, three really. I hope that Google scraps that stupid restriction by geography. It's a round world, and it's all one. Borders don't really apply to communication.