Can I control my image and my identity on the net?

Hello,
i have one question people are aware that this information is (usually) completely public, and the risks they face: misuse (eg, discrimination in hiring), detonating crossings, lifts of old information and that we thought forgotten ...?
For many analysts, the answer is obviously "no". Several signs are on the contrary I think that people, most know well enough what they do. They arbitrate more finely than is saying they think the risks run and the benefits they derive from the sites or networks to which they connect.
• And you, what is your experience? Do you feel you know the risks to privacy that you incur on "social sites, sites for sharing photos, etc.. ? How does this affect whether or not your practice ...
• And for the "experts" are there investigating what people know or not, on how they arbitrate, which they control their image and identity online ..

These practices can undoubtedly put people at risk, yet they are developing at high speed. Three other sets of issues seem to be raised then.
1) The first is the motivation, what drives many individuals to disclose, share biographical information, videos, fleeting feelings, their location, etc.. ? Simple narcissism, or as a result of the secular movement for emancipation of the individual over the social frameworks that have been born? For my part, I favor the second answer.
Is still the first factor to control its identity on the net, it can not appear, or very little, or as synthetic identities. Will it always this possibility? Individuals they may be, one day, under pressure from their peers or even their employers, to join these networks and to expose them?
• And you, what is your experience? What do you and pull you social sites, blogs and so on. where you tell a part of yourself on the Net? Do you feel free to say or to hide what you want? How do you to control your online image ...
• And for the "experts" Narcissism or empowerment, how to share? Is it free to join the network ...

The second set of questions is frequently expressed in the discussions on the new police files : if individuals as easily reveal their political preferences, religious or sexual online, what is embarrassing to that the police (at least) records this information in its own files?
There is of course at least two differences: consent (or the unveiling deliberate) or not and whether or not to lie, even people invent alternatives, nicknames or avatars. But beyond that, the registration has ceased to be a problem? And some sensitive information they have ceased to be? In the name of what, for example, help saying to the social site that I am a leftist Catholic and Gay (three data we have in principle not allowed to register), while it is precisely to meet other gay Catholic leftists I joined this site?
• And you, what is your experience? The filing by the state, traders, by social networks, is it the same? Are there issues that should be prohibited from asking? How often do you lie about you when you are online ...
• And for the "experts": The unveiling of course online allows there over policing? Should we protect people against themselves and if so, how? ...