Many people use the Internet and supply numerous webpages with much private information in 2 ways: consciously and unconsciously. Former and latter are huge topics. Here I would like to say something about the latter.
The unconscious supply of information happens because the average user does not know
- what the applied software and hardware of his/her computer actually does;
- what the visited server actually does.
Of course, in order to know exactly what happens, one has to be an IT-specialist. But some basic things should be clear. Not only because the surfer can put himself in danger, but also because too many naive surfers can put in the long term the non naive in danger, or —at least— make their life harder.
A nice anonymity test is offered by JonDos GmbH here. Green is good, red is bad.