Women love ugly Facebook friends
What has happened to the sisterhood? A quarter of women have admitted splashing pictures of friends in unflattering bikinis on Facebook.
Away from the swimwear, 45 per cent of those polled claimed to have done the same to a friend in an unflattering outfit, while 41 per cent have posted pictures of their friends with no make-up on, a survey of 1500 women for photo gift website Mymemory.com found.
Most of the women posting the photos said they did so after falling out with their friends, while nearly a third said they were taking revenge on people who had done the same to them.
Three-quarters of women said they routinely "de-tagged" photos of themselves if they did not like the pictures, while two thirds polled said they would be "angry" with a friend for uploading unflattering pictures of themselves.
While people can remove their names from pictures, they cannot delete the photograph.
"To see that so many women deliberately commit photo sabotage and upload unflattering pictures of friends is somewhat surprising, particularly when you consider how many said they'd be mad if the same was done to them," MyMemory.com co-founder Rebecca Huggler said.
The survey of 1500 women aged over 18 is more evidence that some people use Facebook at least some of the time to embarrass or humiliate their "friends".
It is not at all the view of Facebook shared by Zuckerberg for the company's less than stellar sharemarket float.
The Facebook IPO filing included a letter from Zuckerberg saying Facebook hoped to strengthen how people related to each other.
"At Facebook, we build tools to help people connect with the people they want and share what they want, and by doing this we are extending people's capacity to build and maintain relationships.
"People sharing more - even if just with their close friends or families - creates a more open culture and leads to a better understanding of the lives and perspectives of others," he said.
"We believe that we have an opportunity to have an important impact on the world and build a lasting company in the process."
Facebook has been extensively studied in its relatively short life, little surprise given its huge popularity.
Some findings have been positive, for example, that viewing and editing Facebook profiles can boost people's self-esteem, or that online social networking can help introverted adolescents learn how to socialise behind the safety of their screens.
Others were not so hopeful, linking Facebook use with narcissism. People who scored highly on a narcissistic personality questionnaire had more friends on Facebook, and even responded more aggressively to derogatory comments about them on the social networking site. Young adults who have a strong Facebook presence show more signs of other psychological disorders, including antisocial behaviours, mania and aggressive tendencies.
Have you posted unflattering photos of 'friends' on Facebook?