Do we reveal too much about ourselves online?

In the few decades since the birth of the web we have embraced email, social networking, and a gamut of online services all of which store more and more data about our lives in the so-called cloud.

But is it realistic to expect that we can keep this data about ourselves private?

Digital and technology writer Tom Chatfield demonstrates for BBC Newsnight how the seemingly trivial details we reveal online every day can be cross referenced and correlated to startling effect.