Shy and introvert people spend more time on Facebook but disclose little information with friends and acquaintances, according to a new study.
"The shy people spend more time on Facebook, but they disclose less information," said Dr Pavica Sheldon, assistant professor in the Communications Arts Department at The University of Alabama in Huntsville (UAH).
For an introvert, using the site doesn't always mean posting to it, she said. The research shows that introverts spend more time there than extroverts do.
"Shy people and people who are more lonely use Facebook to pass the time," Sheldon said.
Even though introverts spend more time, the relationship benefits of Facebook tend to accrue to extroverts, narcissists and people who desire great control over how they present themselves, researchers said.
The more extroverted a person is, the more status posts he or she is likely to make, they said.
"Narcissists like fame, they like to be seen," Sheldon said.
That behaviour accrues more of the social benefits of Facebook to those people, who also are more socially gregarious in person, she said.
"What I found out is that my research supports the 'rich get richer' hypothesis,"  Sheldon said.
"Those users who are richer in their offline relationships will also benefit more from their use of Facebook. The more extroverted you are, the more you will benefit," said Sheldon.
Narcissists and those who score highly in self-monitoring - the ability to alter their behaviour to adjust to changing social situations - tend to post more photos than other users.
"Posting pictures gives them more control over how they are being presented," Sheldon said.
But when all factors are considered, it's the total time spent on Facebook that is the overarching influence when it comes to posting pictures. The more time a user has logged on the site, the more comfortable they become with photo posting.