  The diffusion of novel information through social networks is essential for
dismantling echo chambers and promoting innovation. Our study examines how two
major types of viral channels, specifically Direct Messaging (DM) and
Broadcasting (BC), impact the well-known "strength of weak ties" in
disseminating novel information across social networks. We conducted a
large-scale empirical analysis, examining the sharing behavior of 500,000 users
over a two-month period on a major social media platform. Our results suggest a
greater capacity for DM to transmit novel information compared to BC, although
DM typically involves stronger ties. Furthermore, the "strength of weak ties"
is only evident in BC, not in DM where weaker ties do not transmit
significantly more novel information. Our mechanism analysis indicates that the
content selection by both senders and recipients, contingent on tie strength,
contributes to the observed differences between these two channels. These
findings expand both our understanding of contemporary weak tie theory and our
knowledge of how to disseminate novel information in social networks.
