A troll is usually defined as somebody who provokes and offends people to make them angry, who wants to dominate any discussion or who tries to manipulate people’s opinions. The problems caused by such persons have increased with the diffusion of social media. Therefore, on the one hand, press bodies and magazines have begun to address the issue and to write articles about the phenomenon and its related problems while, on the other hand, universities and research centres have begun to study the features characterizing trolls and to look for solutions for their identification. This survey aims at introducing the main researches dedicated to the description of trolls and to the study and experimentation of methods for their detection.

Features of online social networks are being introduced in various applications and environments, including tools supporting virtual teams and online collaboration in general. In fact, social networking has a large potential for easing collaboration, also across organizational boundaries. However, effective e-collaboration through social networks requires the development of open and interoperable systems, allowing people belonging to different organizations to create ties, reflecting real connections existing in daily activities. Attention has to be paid to identity management, for allowing users to develop their reputation consistently, and to privacy and confidentiality, for creating a more trustful environment and protecting freedom of expression. In this article, the authors propose a novel peer-to-peer system, named Blogracy, leveraging the large BitTorrent network. Its main distinguishing features are: (i) protection of users' identity and privacy, (ii) absence of central control over published content; (iii) interoperability with other systems; and (iv) low costs and scalability of the infrastructure.

This article describes the current landscape in the fields of social media and socio-technical systems. In particular, it analyzes the different ways in which social media are adopted in organizations, workplaces, educational and smart environments. One interesting aspect of this integration, is the use of social media for members’ participation and access to the processes and services of their organization. Those services cover many different types of daily routines and life activities, such as health, education, transports. In this survey, we compare and classify current research works according to multiple features, including: the use of Social Network Analysis and Social Capital models, users’ motivations for participation and organizational costs, adoption of the social media platform from below. Our results show that many of these current systems are developed without taking into proper consideration the social structures and processes, with some notable and positive exceptions.

Participation in social networks has long been studied as a social phenomenon according to different theories. In particular, the notion of social capital highlights a person's benefit due to his relations with other persons, including family, colleagues, friends and generic contacts. It may be important both for the individuals that are able to accumulate large amounts, and for organizations. Nowadays, social networking systems bring many acquaintances online, both in the private and working spheres. Some systems are used both at home, for leisure goals, and on the work place, professionally. In the vast majority of cases, social networking platforms are still used without corporate blessing. However, several traditional information systems, such as CRMs and ERPs, have also been modified in order to include social aspects. This article shows the role of social capital in the participation in online social networking activities, in the various cases of Virtual Organizations, Virtual Teams, and online Networks of Practice. It describes the present situation, which is characterized by great promises and mixed initial results, and some possible prospects.