Hi,
Everyone can get added to the Block All list if you try out Parental Controls in another Mac User Account and don't turn it off before returning to your regular Mac User Account.
You should delete those from the Block List that you want to Contact. (It does not remove them from iChat, just the Block List).
You can then go back to using Block Certain People when the list is back to normal.
It's not that the setting are any different from iChat 4 (and only slightly different from iChat 3). It is understanding how many things can effect what you see.
You can block a Buddy. You Buddy can Block you. In both cases the Buddy will appear Off Line (Although iChat 5 will tell you they are Blocked if you display Off-Line Buddies).
In this case you can consider not Allowing someone as Blocking them (or the Not Allowing you).
As I said test the same iChat Info in another Mac User Account (Managed) with Parental Controls On sends flag to the AIM server to Block all those except any you allow in the Parental Controls. Not undoing the parental Controls before switching back to your regular account will leave that Flag On and your iChat will have everyone in the Block (Specific People) List.
9:14 PM Wednesday; May 5, 2010
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