Entropy-based Classification of 'Retweeting' Activity on Twitter
  Twitter is used for a variety of reasons, including information dissemination, marketing, political organizing and to spread propaganda, spamming, promotion, conversations, and so on. Characterizing these activities and categorizing associated user generated content is a challenging task. We present a information-theoretic approach to classification of user activity on Twitter. We focus on tweets that contain embedded URLs and study their collective `retweeting' dynamics. We identify two features, time-interval and user entropy, which we use to classify retweeting activity. We achieve good separation of different activities using just these two features and are able to categorize content based on the collective user response it generates.   We have identified five distinct categories of retweeting activity on Twitter: automatic/robotic activity, newsworthy information dissemination, advertising and promotion, campaigns, and parasitic advertisement. In the course of our investigations, we have shown how Twitter can be exploited for promotional and spam-like activities. The content-independent, entropy-based activity classification method is computationally efficient, scalable and robust to sampling and missing data. It has many applications, including automatic spam-detection, trend identification, trust management, user-modeling, social search and content classification on online social media. 
Rumi Ghosh, Tawan Surachawala and Kristina Lerman
cs.SI cs.CY