Fig. 1

Topics in hashtag co-occurrence networks. a-e Co-occurrence networks of the most frequent hashtags in each of the five popular topics, where each node denotes a hashtag. The size of a node is proportional to the number of tweets with a hashtag and edge width is proportional to the number of co-occurrences between tags. f Co-occurrences of popular topics involving more than 1000 users, where each node denotes a topic as labeled. The node size is proportional to the number of tweets mentioning a topic and edge width is proportional to the ratio of the number of tweets mentioning both topics over the number of tweets mentioning at least one topic