From Psychology Today:
According to traditional views on privacy-related behaviors, people should carefully consider each piece of personal information, only revealing it if the benefit of doing so outweighs the cost. Since people often disregard costs and benefits when revealing personal information, there’s obviously a problem with the traditional explanation. Perhaps, Carnegie Mellon University psychologists Erin Carbone and George Loewenstein suggest, people do in fact weigh the costs and benefits, but not in the way psychologists have assumed.
In an article they recently published in the journal Current Directions in Psychological Science, Carbone and Loewenstein argue that we all have a drive to disclose that works just like other drives, such as those for hunger, thirst, and sex. In other words, we have a fundamental need to reveal information about ourselves to others. That means that when people decide to disclose something private on a given occasion, the costs and benefits center on satisfying that drive in the moment rather than long-term consequences.