The IRC /ping command lets you determine the network distance between your computer and other users, by returning a report of the network delay between you and another user on a channel.
You can get a listing of the delay between you and everyone else on the channel by pinging the whole channel name.
This information is not necessarily geographically related, since a user in the same town could appear to be farthest away from you if their Internet connection and your Internet connection are far away from each other.
This command is related to the Internet ping command, but run by the IRC server. The times returned by an IRC ping are usually much longer than those of an Internet ping, since IRC communication has more overhead.