The mark command allows you to prevent other CSops from doing a GETPASS or a SETPASS to a room. It can be used to indicate that you are dealing or dealt with a room. Note: Root users can override the mark command.
Example:
/msg chanserv mark #spiderslair password was emailed to founder
The mark is a versatile command in that you can come up with your own uses for mark. The mark will show up in the chanserv info to all CSops, so it can be used to signal anything. It was designed to allow CSops to investigate a room without having anyone else tampering with it, and to mark rooms that have been investigated so that other CSops do not waste time on them. Sometimes users will keep going to different CSops to try to get a password, and the mark helps to deal with this.