Facebook is now the most popular site on the Internet, with more and more people around the world joining every day. But a new article in Slate suggests that the social networking site may in fact be making us unhappy.

Libby Copeland cites new research from Stanford University that found people consistently underestimated how unhappy other people were, and likely wound up feeling more unhappy themselves as a result. Copeland believes the same can be said of Facebook, writing, "By showcasing the most witty, joyful, bullet-pointed versions of people's lives and inviting constant comparisons in which we tend to see ourselves as the losers, Facebook appears to exploit an Achilles' heel of human nature."

Alex Jordan, a postdoctoral fellow who led the Stanford study, suggests it might be a good idea to consider Facebook profiles like airbrushed photos on the covers of women's magazines. Copeland writes, "No, you will never have those thighs, because nobody has those thighs. You will never be as consistently happy as your Facebook friends, because nobody is that happy."