When a newsreader establishes a connection with a news server, it communicates with the remote service using a subset of the NNTP protocol called NNRP. The NNRP protocol defines about twenty commands that a client can send to the server and when the service receives one of these requests it responds by supplying the requested data. Articles are downloaded from the server by every newsreader in this way.
The graphs below show how many clients have sent each NNRP command to the server. Since the server keeps track of the last command sent by each client until it closes the connection regardless of the time elapsed after sending, this graph shows only the number of connected clients who sent each command as the last request.