Human beings have a natural tendency to protect their privacy. It's in our essence to allow only certain people to see who we really are, what we really do, what we really think, and how we really feel. Nowadays Social Networks make us feel more comfortable sharing more information openly and with more people making people's lives less private.
Twitter can feed the narcissistic tendencies of human beings. A large amount of people believe others are interested in the everyday minutia of their lives. Judging by Twitter's initial success and unparalleled growth, it appears to have fulfilled a need for self-expression far beyond what other technologies allow. This incessant broadcasting of people's lives, however, comes with its own set of dangers beyond its pernicious effect of inflating our egos.
When you make private information public it is easier for others to spot your weaknesses and figure out ways to harm or take advantage of you.
It is not uncommon to receive inaccurate feedback from others, which can lead to misunderstandings and/or misinformation.
The information you publish can be taken out of context, making you an easy target for defamation.
People do not fully understand the extent of the impact information disclosure can provoke. Twitter is less than five years old. This is a brand new medium, and we are just now beginning to recognize its potential consequences.
Every one must think hard before they make any data public. Realize that the information, once released, will live forever on the Web. The consideration must always be whether or not it can ever come back to haunt you resulting in any kind of damage (to your reputation, relationships, businesses, job, etc.). It is easy to avoid bad results from happening just by thinking before acting.