OperServ is a component of most IRC services packages used to help administer an Internet Relay Chat network. It provides IRC operators with functions to help monitor and maintain the network, manage the other services, and deal with problematic users.
Some of the more infamous functions of OperServ are the "lines", such as the K-line and G-line. These are used to discipline troublesome network users, however, other network lines are available for use. The exact features available depend upon a particular operator's permissions, and the specific implementation in use.
On DALnet a similar concept known as an "AKill" was used instead of a G-line. The term AKill comes from an earlier implementation in which the IRC services would automatically "kill" (disconnect) the user remotely upon login, rather than the individual servers simply denying the connection.
On OpenNap networks, OperServ is a pseudo-user which allows users above a specific permission level to execute server administration commands. Although primarily intended to supplement clients without built-in support for such actions, there are no restrictions on its use.
Read more about this topic: Internet Relay Chat Services