The recent advances in networking have determined an increasing use of information technology to support interactive networked cooperative applications. Several novel applications have emerged in this area: social networks, distributed virtual environments (DVEs), collaborative learning systems, large-scale crowd-based applications, and mobile collaborative platforms. This kind of applications can be generally referred as Large ScaleCooperative Virtual Environments. The definition of these applications requires affording several challenges such as the design of user interfaces, coordination protocols, mobility models, and proper middleware and architectures supporting distributed cooperation. Collaborative applications may greatly benefit from the support of different kinds of platforms, both cloud and peer to peer and also platforms recently proposed for the Internet of things (IoT) like fog computing. Integration of different platforms, for instance, mobile and cloud environments, is currently a challenge.Furthermore, the analysis and validation of the huge amount of content generated by these applications asks for proper data analysis and processing techniques. The special issue's aim is to investigate open challenges for such applications, related to both the applications' design and the definition of proper architectures. Some important challenges are, for instance, collaborative protocols design, large-scale processing of user information, privacy and security issues, state consistency/persistence, and efficient support definition.This special includes six high-quality papers, five of them are extended versions of the papers accepted and presented at the 4th Workshop on Large Scale Distributed Virtual Environments on Clouds and P2P held in conjunction with Euro-Par 2016 in Grenoble, France, in August 2016. In the following, we give a brief description of each paper.De Salve et al in the paper Predicting the availability of users devices in decentralized online social networks 1 investigate whether availability patterns of users in online social networks (OSNs) can be predicted. The paper proposes a flexible linear predictor whose goal is to estimate the future availability of a user (ie, online or offline) by taking into account only the availability history of that user. The information returned by the predictor is useful to support information allocation/diffusion in distributed OSNs (DOSNs). The predictor may be configured by setting a set of parameters like the size of the period of time in the future to predict and the size of the elapsed period of time exploited for the prediction. Furthermore, the paper proposes several selection strategies to choose users more likely to be online in a time interval. These strategies can be exploited to select the peers which host data replica in a DOSN.The paper Efficient and scalable execution of smart city parallel applications 2 presents an analysis and prediction of internet traffic generated by vehicle and pedestrian devices moving across a "smart avenue". The...