Tuesday, 9 August 2011 is census day in Australia and Aussies will be asked to describe their their age, profession, religion, income and the family makeup in a series of personal questions.

Census question 60 is whether people want to opt-out of having their census records made available in future to historians. If you answer yes, your census information will be kept by The National Archives and made available in 99 years. If you answer “no”, your census details will be destroyed once the statistical data has been aggregated by the Australian Bureau of Statistics.

A survey by Ancestry.com.au found one third of Australians plan to answer “no” to Question 60, even though 80 per cent of people surveyed said that preserving their family history was important to them. In the 18 to 34 age range, 40 per cent said they would answer “no”, and 68 per cent of them identified privacy concerns as the reason for doing so.

As much as I am an advocate of “informed consent”, a census is an important snapshot about the population at the particular time it is taken. Why are people concerned about sharing the data, 99 years from now, after we pass on?

Is it because we don’t want the government to know too much about us? They already do, but in general, data matching rules prevent government from putting all the pieces together in one place.

Is it because we want control over when and how the information is disclosed? Maybe, but then again, we choose (whether directly or implicitly) to disclose heaps more privacy-invasive data about ourselves everyday, on websites like Facebook, Google+ and Foursquare and while shopping, under retailers’ loyalty programs such as Woolworth’s Everyday Rewards.

Is it because storing too much data in one place provides too personal a snapshot? No, and see previous point.

I wonder whether it has to do with the way the question is phrased. I mean, when Facebook wants my permission to use facial recognition (or more accurately, whether I want to opt out) to automatically identify my friends in photos without their permission, Facebook asks me whether it should “suggest photos of me to friends”.

The Ancestry.com.au survey revealed that 7 in 10 Australians are unaware that by saying no (or by not answering the question), their census information will be destroyed.

Perhaps question 60 should instead ask, “Do you want your great great grandkids and historians to be able to learn a little about you?”

Are you inviting someone to burgle your home?

The website Please Rob Me has a straightforward message: Your next instant update on Gowalla, Tweet on Twitter or “I’m at …” status update on Facebook is a broadcast alert to the whole world that you are not at home. And that could make your house a target for burglary.

PleaseRobMe.com

Of course, most people do not share information online about their street address or whether they live alone. But it can be straightforward to piece together enough information by using the surname and city from an online profile and then accessing the local white pages directory.

Whether you share information online and the specific details that you share, are up to you. Sites like Please Rob Me are a good reminder about the implications of sharing tidbits of information that seem innocuous on their own but can can reveal quite specific information when taken together.

Forbes magazine’s Velocity blog, CNET’s The Social and the Canadian privacy commissioner have each profiled PleaseRobMe.com.

(In legal terms, “robbery” is the act taking of the property of someone from their person or in their immediate presence, against their will, by the use of violence or intimidation. “Burglary” is the act of breaking into and entering a house or building with intent to steal. But I suppose that “Please Burgle Me” doesn’t have quite the same ring to it.)