By 2020, large-format flat-panel screens will be so cheap and ubiquitous, they will have replaced most pictures on most walls in most houses.

Many of those screens will have cameras that watch what we are doing, try to make sense of it, and react. Many of them will coordinate their actions as we move through the house. It will feel like we have “tunneling” windows to other parts of the world, some of them to people, some to places, some to data.

Much of the data will be transmitted to outside the house, raising a host of new security and privacy problems.