Anonymity and Identity Online

Economics Job Market Rumors (EJMR) is an online forum and clearing house for infor-
mation about the academic job market for economists. It also includes content that is
abusive, defamatory, racist, misogynistic, or otherwise “toxic.” Almost all of this content
is created anonymously by contributors who receive a four-character username when post-
ing on EJMR. Using only publicly available data we show that the statistical properties of
the scheme by which these usernames were generated allows the IP addresses from which
most posts were made to be determined with high probability.1 We recover 47,630 distinct
IP addresses of EJMR posters and attribute them to 66.1% of the roughly 7 million posts
made over the past 12 years. We geolocate posts and describe aggregated cross-sectional
variation—particularly regarding toxic, misogynistic, and hate speech—across sub-forums,
geographies, institutions, and IP addresses. Our analysis suggests that content on EJMR
comes from all echelons of the economics profession, including, but not limited to, its elite
institutions.