In one report, Dutch and American psychologists found students using the website while they study -- even off and on -- saw their grades drop 20 percent, compared to students who do not study while on Facebook.
In the second study, researchers discovered the site draws a large number of people with higher levels of narcissism and low levels of self-esteem. Researchers at York University say Facebook-users see the site as a means of self-promotion.
That promotion breaks down by gender: women are most likely to advance themselves via photographs -- while men do so in written postings.
