On December 11th 2010, we noticed that something got wrong with Yahoo Messenger Chat Room List: one or more Chat Room has disappeared from the List!! Though some others are not!: Chat Room List Yahoo got Error!!
To make you able to join your lovely Room (if you can’t join to your Chat Room of YM because it also missing / gone), just open random Room or any Chat Room available in the list, and then join it manually by using Join Room Command:
/join yourfavoriteroom:1 | /join singapore:1
That would help you to join your favorite room! Enjoy