  Contributing to the writing of history has never been as easy as it is today
thanks to Wikipedia, a community-created encyclopedia that aims to document the
world's knowledge from a neutral point of view. Though everyone can participate
it is well known that the editor community has a narrow diversity, with a
majority of white male editors. While this participatory \emph{gender gap} has
been studied extensively in the literature, this work sets out to \emph{assess
potential gender inequalities in Wikipedia articles} along different
dimensions: notability, topical focus, linguistic bias, structural properties,
and meta-data presentation.
  We find that (i) women in Wikipedia are more notable than men, which we
interpret as the outcome of a subtle glass ceiling effect; (ii) family-,
gender-, and relationship-related topics are more present in biographies about
women; (iii) linguistic bias manifests in Wikipedia since abstract terms tend
to be used to describe positive aspects in the biographies of men and negative
aspects in the biographies of women; and (iv) there are structural differences
in terms of meta-data and hyperlinks, which have consequences for
information-seeking activities. While some differences are expected, due to
historical and social contexts, other differences are attributable to Wikipedia
editors. The implications of such differences are discussed having Wikipedia
contribution policies in mind. We hope that the present work will contribute to
increased awareness about, first, gender issues in the content of Wikipedia,
and second, the different levels on which gender biases can manifest on the
Web.
