Data from: The topology of a discussion: the #occupy case

Introduction: We analyse a large sample of the Twitter activity that developed around the social movement 'Occupy Wall Street', to study the complex interactions between the human communication activity and the semantic content of a debate. Methods: We use a network approach based on the analysis of the bipartite graph @Users-#Hashtags and of its projections: the 'semantic network', whose nodes are hashtags, and the 'users interest network', whose nodes are users. In the first instance, we find out that discussion topics (#hashtags) present a high structural heterogeneity, with a relevant role played by the semantic hubs that are responsible to guarantee the continuity of the debate. In the users’ case, the self-organisation process of users’ activity, leads to the emergence of two classes of communicators: the 'professionals' and the 'amateurs'. Results: Both the networks present a strong community structure, based on the differentiation of the semantic topics, and a high level of structural robustness when certain sets of topics are censored and/or accounts are removed. Conclusions: By analysing the characteristics of the dynamical networks we can distinguish three phases of the discussion about the movement. Each phase corresponds to a specific moment of the movement: from declaration of intent, organisation and development and the final phase of political reactions. Each phase is characterised by the presence of prototypical #hashtags in the discussion.

引言：本研究针对围绕占领华尔街（Occupy Wall Street）社会运动产生的大量推特（Twitter）活动样本展开分析，旨在探究人类传播活动与辩论语义内容之间的复杂交互关系。
方法：本研究采用基于@用户-#话题标签（@Users-#Hashtags）二分图（bipartite graph）及其投影网络分析的网络研究方法，其中投影网络包含两类：一是以话题标签为节点的语义网络（semantic network），二是以用户为节点的用户兴趣网络（users interest network）。首先，本研究发现讨论主题（#hashtags）呈现出高度的结构异质性，且语义枢纽（semantic hub）在保障辩论延续性方面发挥着关键作用。就用户群体而言，用户活动的自组织过程催生了两类传播者："专业传播者"与"业余传播者"。
结果：两类网络均展现出基于语义主题分化的显著社区结构，且在部分主题被屏蔽或账号被移除的情况下，仍保持较高的结构鲁棒性（structural robustness）。
结论：通过分析动态网络的特征，本研究可将围绕该运动的讨论划分为三个阶段。每个阶段对应该运动的特定发展节点：意图声明阶段、组织发展阶段以及最终的政治回应阶段。各阶段均以讨论中存在典型#话题标签（#hashtags）为核心特征。