The 2014 Special issue of Computer Communications is dedicated to opportunistic networks (OppNets), which are an instance of the delay tolerant networking (DTN) paradigm. There are three algorithmic papers that propose and evaluate new forwarding schemes for opportunistic networks. GAR, a group-aware forwarding scheme is introduced in a paper for cooperatively transferring messages in an opportunistic network. Alongside the forwarding strategy, this work also introduces a buffer management strategy in which the message dropping priorities are chosen so as to minimize the loss in delivery probability. In one paper, an analytical model for the delay and the number of hops that encompasses both social-aware and social-oblivious single-copy forwarding protocols, as well as different hypotheses for user contact dynamics is discussed. Finally, the special issue also includes two papers that consider instances of the opportunistic paradigm applied to vehicular ad hoc networks (VANETs).