People with excess of self-love might choose networking sites like Facebook for unabashed self-promotion and publicity.
They are more likely to choose glamorous pictures for their main profile photos, while others are more likely to use snapshots, according to a Georgia University study.
"We found that people who are narcissistic use Facebook in a self-promoting way that can be identified by others," said Laura Buffardi, a doctoral student in psychology who co-authored the study with associate professor W. Keith Campbell.
Buffardi and Campbell chose Facebook because it's the most popular networking site among college students with a 100 million strong membership and because it has a fixed format that makes it easier for researchers to compare user pages, according to an Eurekalert report.
"Narcissists might initially be seen as charming, but they end up using people for their own advantage," Campbell said. "They hurt the people around them and they hurt themselves in the long run."
The researchers distributed questionnaires to nearly 130 Facebook users, analysed the content of the pages and had untrained strangers view the them and rate their impression of the owner's narcissism.
Untrained observers were able to detect narcissism, too. The researchers found that they used three characteristics - quantity of social interaction, attractiveness of the individual and the degree of self promotion in the main photo - to form an impression.
"People aren't perfect in their assessments," Buffardi said, "but our results show they're somewhat accurate in their judgements".
"Nearly all of our students use Facebook, and it seems to be a normal part of people's social interactions," Campbell said. "It just turns out that narcissists are using Facebook the same way they use their other relationships - for self promotion with an emphasis on quantity of over quality."
"We've undergone a social change in the last four or five years and now almost every student manages their relationships through Facebook - something that few older people do," Campbell said. "It's a completely new social world that we're just beginning to understand."
These results will appear in the October issue of Personality and Social Psychology Bulletin.