Just a week ago, Google opened up the Chromecast markets to sell the uber-device in Europe and Canada. Its inventory has already sold out in both the UK and Norway. In fact, Curry's (which is a popular store chain in Europe) was selling a Chromecast ever 4.5 seconds on the day of launch. A rep from that company indicated this was "one of the most successful launch days" both online and in brick and mortar stores for the Chromecast. This success rivals the amazing launch the device had in the US as well.
It just goes to show that when you make a solid device that fills a niche, and then offer it at an affordable price, people will flock to it.
As a sidenote - it turns out the Nexus 5 is one of Google's top sellers as well.
Source: GigaOM