  Community or modular structure is considered to be a significant property of
large scale real-world graphs such as social or information networks. Detecting
influential clusters or communities in these graphs is a problem of
considerable interest as it often accounts for the functionality of the system.
We aim to provide a thorough exposition of the topic, including the main
elements of the problem, a brief introduction of the existing research for both
disjoint and overlapping community search, the idea of influential communities,
its implications and the current state of the art and finally provide some
insight on possible directions for future research.
