  Most research of online communication focuses on modes of communication that
are either open (like forums, bulletin boards, Twitter, etc.) or direct (like
e-mails). In this work, we study a dataset that has both types of communication
channels. We relate our findings to theories of social organization and human
dynamics. The data comprises 36,492 users of a movie discussion community. Our
results show that there are differences in the way users communicate in the two
channels that are reflected in the shape of degree- and interevent time
distributions. The open communication that is designed to facilitate
conversations with any member, shows a broader degree distribution and more of
the triangles in the network are primarily formed in this mode of
communication. The direct channel is presumably preferred by closer
communication and the response time in dialogues is shorter. On a more
coarse-grained level, there are common patterns in the two networks. The
differences and overlaps between communication networks, thus, provide a unique
window into how social and structural aspects of communication establish and
evolve.
