  Online social media are information resources that can have a transformative
power in society. While the Web was envisioned as an equalizing force that
allows everyone to access information, the digital divide prevents large
amounts of people from being present online. Online social media in particular
are prone to gender inequality, an important issue given the link between
social media use and employment. Understanding gender inequality in social
media is a challenging task due to the necessity of data sources that can
provide large-scale measurements across multiple countries. Here we show how
the Facebook Gender Divide (FGD), a metric based on aggregated statistics of
more than 1.4 Billion users in 217 countries, explains various aspects of
worldwide gender inequality. Our analysis shows that the FGD encodes gender
equality indices in education, health, and economic opportunity. We find gender
differences in network externalities that suggest that using social media has
an added value for women. Furthermore, we find that low values of the FGD are
associated with increases in economic gender equality. Our results suggest that
online social networks, while suffering evident gender imbalance, may lower the
barriers that women have to access informational resources and help to narrow
the economic gender gap.
