1) What is Privacy
Privacy can simply be defined as the right to be left alone. 'It is a comprehensive right and it is the right most valued by a free people.
It is a fundamental human right. A society in which there was a total lack of privacy would be intolerable; but then again a society in which there was a total privacy would be no society at all’ (the is a balance needed).
Privacy is the right of people to make personal decisions regarding their own intimate matters, it is the right of people to lead their lives in a manner that is reasonably secluded from public scrutiny, and it is the right of people to be free from such things as unwarranted drug testing or electronic surveillance (edited from Answers.com
http://www.answers.com/topic/privacy)
UN Declaration of Human Rights.
The UN Declaration of Human Rights defined Privacy as this:
No one shall be subjected to arbitrary interference with his privacy, family, home or correspondence, nor to attacks upon his honour and reputation. Everyone had the right to the protection of the law against such interference or attacks.
Without Privacy Without privacy life would be hell. It would mean that you would be highly vulnerable to the control of others, you would lose your freedom which may lead to inhibition and tentativeness and you may be less spontaneous and you would be more likely to be manipulated.
Reference:
http://www.craigbellamy.net/2006/04/24/privacy/