Chromecast is a small TV dongle based off Android, and used as part of the Chrome brand. The device is manufactured by Google, and connects to televisions through an HDMI port. It was announced on July 24, 2013, and went on sale later that day.
The device is able to connect to certain mobile apps and websites, and stream the same content that is being viewed on the the other device. It is compatible with all operating systems Chrome works on, including Android, iOS Windows, Mac, etc. and the Chromebook Pixel. It can also connect to certain sites, such as YouTube.
Currently, Chromecast can sync with Pandora, Hulu Plus, HBO GO, YouTube, Netflix, Google Play Music, Movies and TV, and several other apps on all devices. It is also able to cast tabs via a Chrome extension on certain computers. A full list of supported apps can be viewed on the official page. On February 3, 2014, Google opened up the developer SDK to the public, allowing anyone to create apps that work with the Chromecast.