They gave notice at the end of April, and have not missed the appointment although it seems to have been rather gradual. Apple has closed the tap and we no longer have AIM integration within the iChat protocol with Apple accounts that have a @mac.com or @me.com address. We could say that this is the end of an era where, at least in the United States, AIM was one of the absolute kings of instant messaging.
If your Apple account doesn’t have any of these addresses, you can forget about it. But if you have used AOL Instant Messenger with an Apple account that ends in mac.com or me.com, the bad news is that you will no longer be able to identify yourself on that messaging service with your Apple account.
So if you were still using AIM, you’d have to create a new user account from scratch and refill your friends list. I doubt this will affect many people, considering that mobile messaging has wiped out all the old “desktop” protocols, but the statistics never fail and someone must have stumbled across the cut this week. Remember that you can always use the native AOL client to do this.