finger
Finger is a program to display information about users.
If finger is enabled on the remote machine, you may be given information on the user's real name, if they are logged in or not, if they have mail, and if they have a .plan file in their home directory, it might be displayed for you.
Finger is normally associated with a user@hostname address, which may or may not be the same as a users email address.
Most Internet Service Providers no longer allow finger access, so, you may find that you get no useful answer for most people.
Other people use their local .plan file to hold such information as PGP keys, the fact they are on vacation, and all sorts of information.
Use the finger kioslave like this: finger://username@hostname
See the manual: finger.