Learn the number of buddies allowed in an iChat Buddy List and what can happen if you go over the limit.
If too many people are in your list and you try to add another, the Buddy's status is incorrect or not listed. If you quit and reopen iChat, the Buddy no longer appears in the Buddy List.
This can happen when you have more Buddies in your list than the AOL Instant Messenger network allows. The current limit for the number of Buddies in a Buddy List is 200. However, you may need over 190 Buddies before this issue occurs.
If you're at or close to the limit, delete people from your list before you add more.