Every home, it was promised in the 1960s, would have a robot butler. So far those sturdy and reliable companion robots of our imaginations have remained just that. And even as the technology to develop humanoid robots races ahead of us, in 2013, it has been the arrival of funny little disk-shaped and flattened UFOs circling our floors, picking up dust and other crumbs, that has defined home-automation in the early 21st century more than any other technology.