u - Registered Channel User
Sets a user to +u. He/she will be identified with a - in front of the nickname. While adding someone to the UOP list gives them certain abilities, moding them +u does not. However, it can be used as an indicator. What it would indicate would be up to each room to decide, a help room might use it to show a guest helper, a chat room might use it to show that the person was friends with one of the regulars, but not themselves around and trusted enough to have earned voice or ops. Or perhaps everyone is moded +u on joining and then they lose that status if they misbehave. Then you could tell if someone just made one mistake or is being a repeat troublemaker whom you might then wish to ban. It should be used however best suits the needs of the room. It's also a convenient when using MemoServ as a mailing list, as you can send a memo to all the UOPs in a room. Convenient for communnities and events.
Privilege: Channel Operator
Examples:
/mode #webchat +u Mark
/mode #webchat +uuu Mark Jennifer Estrella
U - Enable Channel Knocks
When this mode is set and user tries to join the channel it will send a knock to the channel operators telling them that a user is trying to join. This will allow the channel operators to INVITE that user into the channel.
Privilege: Channel Operator
Examples:
/mode #webchat +u