This command is used to gain founder access to a room, level 7 access as shown by the acc and access commands. After identifying to a room, you have complete control over it and can use any of the services commands that relate to room management.
Example:
/msg chanserv identify #conferenceroom mypass
This command should be used when you own a room and wish to make changes to its settings. As founder you should not need to identify with the room's password very often. You should be opped based upon your nick, and if need be, identify for your nick.
The room won't expire so long as the founder's nick does not and people get opped in the room regularly. If a root sets keep on for the room, then it will not expire from lack of use.
Note: Service commands are deprecated, and this command is no longer needed at all, because channels are attached to a nick directly, without a password.