m - Messages:
This will protect you from getting direct messages from other users. This is useful if you are away and do not want people trying to communicate with you or if you do not want to be bothered outside of rooms. It also is a good mode to set for children.
While it is best to either supervise a child or educate them thoroughly and only allow them to chat unsupervised when their guardians feel they are ready, removing private messages provides some additional protection. Then if they remain in well-supervised rooms the operators may make sure that the conversation is acceptable.
Privilege: User
Examples:
/mode Dan +m
/umode +m