Harper Reed - who calls himself, with characteristic understatement "probably one of the coolest guys ever" - was the Chief Technology Officer for President Barack Obama's 2012 re-election team.

It became famous for building the most sophisticated voter-checking database ever seen in a US presidential election.

By using information from social networks, television viewing habits and personal donation histories it was able to micro target individual voters, sending them millions of personalised emails and tweets each day.