Online tracking debate heats up after flaws exposed

North Carolina resident Dan Tynan has taken a stand against marketing companies that track his movements online by exposing the comical inaccuracies of the data they collect.

After noticing several ads for mobile phones for the elderly as he browsed the web, Tynan discovered that hundreds of marketers were tracking his every move and coming to inaccurate conclusions about his identity.

"Some thought I was a soccer mom and some thought I was a trendy homemaker," says Tynan, who is clearly neither.

Privacy advocates warn collecting data about individuals through the web could be dangerous, for instance because it could enable groups like insurance companies to make assumptions that could hurt consumers.

Meanwhile, US policymakers have been debating a series of proposals labelled Do Not Track, which would enable internet users to turn off online ad tracking.

But the Direct Marketing Association, which represents online marketers, says most internet users know they are being tracked online and find the ads helpful.

Created by the BBC's Matt Danzico