USENET is a network of servers that exchange messages posted by users. Each host is connected to a number of other servers, called its 'peers', and sends them all the posts it receives from local clients and remote peers. The graphs below show how many TCP / IP connections have been used to exchange messages with other peers.
Since each server uses different connections to receive and send messages, the graphs show the number of remote peers connections to this server (Incoming connections) separately from the number of connections established by this host to its peers (Outgoing connections).
Since the number of connections established by each server depends on the volume of messages to be transferred, the number of connections is a rudimentary measure of traffic.