networks and their value from a multiplex perspective*.

Recently, empirical models of multilayer networks have emerged to address the multi-relational nature of social networks [@kivela2013; @Szell19072010]. In such models, interactions are considered as layers in a systemic view of the social network. We adopt such a model in our analysis, where we shift the concept of a link and neighbourhood to encompass more than one network. This allows us to study interactions and structural properties across online social networks (OSNs), addressing the need for further understanding of their complimentary and overlapping nature, and multiplexity online. Although there have been some recent comparative studies of multiple online social networks [@ICWSM148059; @lee2014], and their intersection [@Szell19072010], the applications of multiplex network properties to OSNs is yet to be substantially addressed.

In this work, we explore intersecting networks, multiplex ties, and their application to link prediction across OSNs. Link prediction systems are key components of social networking services due to their practical applicability to friend recommendations and social network bootstrapping, as well as to understanding the link generation process. Link prediction is a well-studied problem, explored in the context of both OSNs and location-based social networks (LBSNs) [@liben2007link; @menon2011link; @crandall2010; @scellato2011exploiting]. However, only 