Abstract
According to the «echo chamber» hypothesis, political networks on the internet are fragmented and limiting. Online political communication basically preaches to the converted with little or no possibility to influence opinions, spread new ideas, or ensure a plurality of views. If this is the case, exposure on the web is constrained to reinforcement inside more or less ideologically homogenous communities, and to silence or polarization towards politically divergent networks. However, constant expansion in the use of social media platforms and fluidity in voter choices oblige us to re-examine the dynamics of political networks, particularly in contexts of extreme uncertainty and polarization. Moreover, the popularity of the echo-chamber claim has neglected important functions and dynamics of online political networks such as the relation between network structure and discourse.

This paper addresses these issues by examining the connectedness among political networks on Twitter. We explore dynamics inside and between the far right and the far left, as well as the relation between the structure of the network and political vocabulary. The 2015 Greek political context offers a unique opportunity to investigate political communication in times of political intensity. We explore interactions inside and between political networks on Twitter in the run up to the elections of three different ballots: the parliamentary election of 25 January, the bailout referendum of 5 July, the snap election of 20 September; we, then, compare political action during campaigns with that during routinized politics. 

Lamprini Rori is  the 2016-2017 A.G. Leventis Foundation Visiting Fellow at Modern Greek Studies at St Antony’s College. Her current research focuses on radicalisation, right-wing extremism, radicalism, the role of emotions in political behaviour, traditional and social media effects. She holds a PhD in Political Science from Université Paris I, Panthéon-Sorbonne. Her thesis « Les organisations partisanes à la lumière de la professionnalisation de la communication politique: une présidentialisation inachevée. Analyse comparative du Parti socialiste français et du Mouvement socialiste grec” examined how the professionalization of political communication affected the organizational change of socialist parties in Europe and most particularly in France and Greece. Lamprini also holds an MA in Political Sociology and Public Policy from Sciences Po Paris and an MA in Political and Social Communications from Paris I University. She has published extensively on Greek elections and parties and the rise of right-wing extremism. Her articles appear, among others, in Party Politics, West European Politics, Pôle Sud. 

Jonathan Bright is a Research Fellow at the Oxford Internet Institute who specialises in computational approaches to the social and political sciences. He has two major research interests: exploring the ways in which new digital technologies are changing political participation; and investigating how new forms of data can enable local and national governments to make better decisions.

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