About the authors

Katrin Weller is an information scientist at GESIS – Leibniz Institute for the Social Sciences in Cologne (Germany). From 2006 to 2012 she worked at the Department of Information Science at Heinrich-Heine-University Düsseldorf. She is co-editor of Twitter and Society (2014). Her research interests include interdisciplinary methods in social media studies, altmetrics and web science.
GESIS – Leibniz Institute for the Social Sciences, Data Archive for the Social Sciences, Unter Sachsenhausen 6–8, D-50667 Köln, Germany, Phone: +49 221 47694 472

Markus Strohmaier is a Full Professor of Web-Science at the Faculty of Computer Science at University of Koblenz-Landau, Germany and Scientific Director of the Computational Social Science department at GESIS – the Leibniz Institute for the Social Sciences, Germany. His main research interests include web science, social and semantic computing, computational social science, networks and data mining.
GESIS – Leibniz Institute for the Social Sciences, Computational Social Science, Unter Sachsenhausen 6–8, D-50667 Köln, Germany
©2014 Walter de Gruyter Berlin/Boston