Why do people post everything about their lives on Facebook?

Attention seekers might do anything to grab the attention of others. This desire to grab attention might motivate those people to keep posting anything that happens to them on social networks.

People who are easily provoked are more likely to speak about the things that triggered their emotions. Those people are more likely to share everything online.

Not all narcissists share their personal life details with others, but some of them do. A narcissist believes that they are very important and so they believe that everything they say or share is of extreme importance.

According to psychologists, a person might post many details about their lives if they feel lonely. Those people might do so in order to connect with others and experience some intimacy.

People who have an overly active medial prefrontal cortex, the area responsible for personality expression, might be hardwired to share more. Some scientists believe that those people are hardwired to be this way.

Some people don't have any kind of privacy concerns. Those people don't mind sharing every little detail about themselves online.

A person who has a self-regulation problem might find it hard to prevent themselves from sharing private information of themselves online.

People who trust others very easily might have no problem posting private information about themselves online.

People who post very often might be insecure about themselves and their self-image. Those people might keep posting in order to change other's opinion of them.