Directly you can use these simple and very useful chat commands on Yahoo! Messenger.
Yahoo! Chat Commands:
/join [room] go to what ever room you wish
/invite [buddys name] sends invitation request
/tell [user] [message] private messages a friend
/follow [user] follows a friend
/stopfollow [user] stop following someone
/stopfollow [yourname] to stop them from following you
/goto [user] enters the room the user is in/away [off] turn your private messages back on
/think [message] (type this to think what you want
/ignore [list] list everyone who you are ignoring
/ignore add [user] add someone to your ignoring list
/ignore [add all] ignores everything going on.