A Dutch man voluntarily handed a weeks worth of mobile phone data over to researchers. Ton Siedsma allowed researchers access to the same type of metadata that intelligence agencies would collect, including phone and email header information, by letting the researchers install a data-collecting app on his phone. Using his browser data, we were able to see the sites he visited and the searches he made. And we could see the subject, sender and recipient of every one of his emails. Researchers also found that Ton would be like candy to online marketers.”]