In light of the erosion of privacy online, we need to be careful to protect our privacy at home, according to Michael Birnhack, law professor at Tel Aviv University, speaking at Intelligence Squared's If conference.

In direct contrast to Martin Blinder's argument in favor of personal analytics, Birnhack said: "Yes we can measure stuff, but do we want to measure all that stuff? I would argue that at least some of us would like to maintain a place where nothing is measured and nothing should be measured."

We have always used technology to maintain privacy within our properties, such as locks, curtains, shades, CCTV, and security systems, and a person's home has always provided a degree of privacy where you can do what you like. Birnhack contrasted this with the life of homeless people—who must live their lives out in public. "Privacy in the home is the management of the boundaries between me and you," he said. It is not clear who always makes that decision.

Birnhack was particularly concerned with the impact of technologies like Google Street View on privacy in the home. He made a comparison between having a stranger walk past and look into your home with Street View.

He said that many London houses have large windows, allowing people walking up and down the street to peer in. "But it's rare for someone to stand and stare inside. The person inside would then feel nervous, close the curtains, call the police and it could even get violent," he said. He explained that although people can see inside these houses quite easily, they don't, because there's a social norm that dictates that you shouldn't.

Google Street View, on the other hand, is permanent and opens up the windows of your house to a world beyond the people who walk down your street. But the main difference is the privacy implications. "I can't open my window and yell at Google's camera to get out of here. There's no social norm—they are completely irrelevant."

Birnhack is particularly concerned about thermal imaging, which has been used to spot criminals in their home growing cannabis with energy and heat-intensive hydroponic systems. Similar technology have been used recently by the Telegraph to see if protestors at St. Paul's were in their tents at night during the Occupy LSX protests. He said: "They have a technology that becomes more ubiquitous and once again it bypasses social norms but it also bypasses locks, curtains, and windows."

He called for careful consideration of the implications of these technologies for privacy and perhaps even legislation to control their use.