Rory Cellan-Jones and privacy expert George Danezis
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Can Rory go a day without data?

Big data is said to be changing industries around the world. From targeted advertising to streamlining production, thousands of jobs are being created and big promises are being made.

The data, however, comes from each of us, often from the moment we wake up to the time we go to bed. So is it possible to spend a day in a city and not share any data?

BBC technology correspondent Rory Cellan-Jones gave it a go.

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