Contributive Social Capital Extraction From Different Types of Online Data Sources

It is a recurring problem of online communication that the properties of unknown people are hard to assess. This may lead to various issues such as the spread of `fake news' from untrustworthy sources. In sociology the sum of (social) resources available to a person through their social network is often described as social capital. In this article, we look at social capital from a different angle. Instead of evaluating the advantage that people have because of their membership in a certain group, we investigate various ways to infer the social capital a person adds or may add to the network, their contributive social capital (CSC). As there is no consensus in the literature on what the social capital of a person exactly consists of, we look at various related properties: expertise, reputation, trustworthiness, and influence. The analysis of these features is investigated for five different sources of online data: microblogging (e.g., Twitter), social networking platforms (e.g., Facebook), direct communication (e.g., email), scientometrics, and threaded discussion boards (e.g., Reddit). In each field we discuss recent publications and put a focus on the data sources used, the algorithms implemented, and the performance evaluation. The findings are compared and set in context to contributive social capital extraction. The analysis algorithms are based on individual features (e.g., followers on Twitter), ratios thereof, or a person's centrality measures (e.g., PageRank). The machine learning approaches, such as straightforward classifiers (e.g., support vector machines) use ground truths that are connected to social capital. The discussion of these methods is intended to facilitate research on the topic by identifying relevant data sources and the best suited algorithms, and by providing tested methods for the evaluation of findings.