If you use AIM to chat with your friends and family, it is doubtful that you want to chat with any and everybody that uses AIM. To limit what users can contact you, follow these steps:
1. Click Edit and select Settings.
2. Select the Privacy tab.
3. Under Who can contact me, select either Allow only users on my Buddy List or Allow only the users below and use the corresponding text box to add the desired users to your Allow List.
4. Click Save.