Are you using Groups ?
If so when the Slide pane comes out of the Buddy List to Add a Buddy does it suggest which Group it is going to Add the Buddy to ?
I have renamed some of my Groups between iChat 2 and now.
The
Picture here shows a potential Buddy would be added to my "Regulars" group in iChat 4 (As an AIM Buddy).
I have been reading that AOL developers site It mentions Groups and Smart groups but does not state what consists of a Smart Group.
My guess it is something to do with the "Recent Buddies Group"
In the PC application AIM 5.9 or above all Buddies that contact you tend to get added to this group.
By Default it is not turned On for iChat.
However in iChat 4 you get the option to use it.
See the checkbox under the word Name that I have added to
this Screen Shot
Even if you enable this group it does not appear in the list of Groups you can Edit (Plus button you Mentioned > Edit Groups)
Before AIM brought out the current version of AIM for Mac (ver 1.1) the Previous one was used to delete this group once you had removed buddies from it.
However a Right-Click once the group name bar has been clicked will bring up a contextual Menu where you can delete it.
It may pay to Enable this group fisrt and see if it has any Buddies in it and "Save" buddies by dragging them to the Proper groups.
NOTES.
In iChat 2 it was possible to drag Buddies into a different Group
This actually added then to more than one Group unless you then delete them from the other.
The Previous AIM for Mac (ver 4.7) also worked this way.
Currently iChat 4 seems not to let you add Buddies to more than one group.
(not even with Modifier keys)
This does seem odd as iChat 2 counted every entry or every group and added that as the total number of Buddies you had.
This used to cause issues with the Buddy List Limit being only 200. It is not precisely known what figure this is now although I have seen 600 mentioned.
5:30 PM Sunday; March 22, 2009