Brett Gaylor is a Canadian filmmaker whose new documentary focusses on the sometimes shadowy industry that's surrounds tracking and sharing information about your online activities.
Because most of the time you trawl the internet, like or comment on something, or use an app, somebody is recording what you do. Then this information is being shared with others to present you with more effective, targeted ads.
Mr Gaylor's seven-part online documentary, called Do Not Track, is clever about how it presents this story too. It puts you at the centre of the action by asking you to share information about your favourite websites so you can see how they spread information about you around the web.
Mr Gaylor told This Way Up's Simon Morton that "We are all commodities in a way...With the web we have got used to the idea that everything is free, that you can look at your favourite newspaper or you can watch funny videos on You Tube. But there is no such thing as a free lunch...! Someone is paying to get your attention."