  Gossiping is a communication mechanism, used for fast information
dissemination in a network, where each node of the network randomly shares its
information with the neighboring nodes. To characterize the notion of fastness
in the context of gossip networks, age of information (AoI) is used as a
timeliness metric. In this article, we summarize the recent works related to
timely gossiping in a network. We start with the introduction of randomized
gossip algorithms as an epidemic algorithm for database maintenance, and how
the gossiping literature was later developed in the context of rumor spreading,
message passing and distributed mean estimation. Then, we motivate the need for
timely gossiping in applications such as source tracking and decentralized
learning. We evaluate timeliness scaling of gossiping in various network
topologies, such as, fully connected, ring, grid, generalized ring,
hierarchical, and sparse asymmetric networks. We discuss age-aware gossiping
and the higher order moments of the age process. We also consider different
variations of gossiping in networks, such as, file slicing and network coding,
reliable and unreliable sources, information mutation, different adversarial
actions in gossiping, and energy harvesting sensors. Finally, we conclude this
article with a few open problems and future directions in timely gossiping.
