  Many real-world relations can be represented by signed networks with positive
and negative links, as a result of which signed network analysis has attracted
increasing attention from multiple disciplines. With the increasing prevalence
of social media networks, signed network analysis has evolved from developing
and measuring theories to mining tasks. In this article, we present a review of
mining signed networks in the context of social media and discuss some
promising research directions and new frontiers. We begin by giving basic
concepts and unique properties and principles of signed networks. Then we
classify and review tasks of signed network mining with representative
algorithms. We also delineate some tasks that have not been extensively studied
with formal definitions and also propose research directions to expand the
field of signed network mining.
