I don't see all my contacts on my Messenger List
Description
This article explains how to show your offline friends on your Messenger List.
Resolution
The Show Offline Contacts option may be un-checked. If contacts are not currently on Yahoo! Messenger, they won't show up.
To find out, go to the View menu and look for Show Offline Contacts. Make sure this option is checked so you can see all your friends even when they're offline.