ChanServ allows you to register and control various aspects of channels. ChanServ can prevent malicious users from "taking over" channels by limiting who is allowed channel operator priviliges.
MemoServ allows you to send short messages to other IRC users, whether they are online at the time or not. Both sender and recipient must have their nicknames registered with NickServ in order to send a memo.
Oper Commands - Commands used only by IRC operators.