There is a certain species of proud person — the one who comes across as somewhat courageous, but who is in fact much more naïve — who will apparently fearlessly declare that they have nothing to hide. What most of these sort of people overlook is their own foolish pride.
Whether they are more or less upstanding than you or I is not the issue. There is no secret police ready to jump out from behind a bush. In the vast majority of cases, crime is not what online privacy is about at all. Instead, when large masses of illiterate buffoons wholeheartedly expose themselves online, they quite simply make it so much easier for the propaganda machines to exploit their ignorance.
For example: Imagine a person could be predicted to click on a certain type of image — wouldn’t it be child’s play to offer that person such images, linking them to content that the advertising agency earns revenue on? Wouldn’t it be a stupendously simple algorithm to get such suckers addicted to such a machine, thereby churning out cash like there’s no tomorrow? And of course the cherry on top would be to present the suckers with the reward they were seeking all along after they were good little lab rats and clicked the appropriate links.
The truth doesn’t matter at all — you can always find someone willing to make any kind of argument online … and the fools are more than willing to rush in time after time. Every time, over and over: kaching, kaching, KACHING! (see also “The Social Construction of Publishing“)