How can I keep people I don't know from sending me instant messages?
People who know your e-mail address can send you messages even if they are not on your contact list or on your Allow List. You can prevent this by adjusting your privacy settings.
1. In the Messenger main window, click the Tools menu, then click Options.
2. Click the Privacy tab.
3. Under the heading My Allow List, click All others, then click the Block button.
All others moves to your Block list. This forces anyone who wants to send you messages to add you to their own contact list. Click the OK button once you have done this.
4. To block a message from an individual, simply click the Block button on the toolbar in the conversation that you are having.
The blocked contact does not know he or she has been blocked. You simply appear to be offline to them.
Deleting a blocked person from your contact list does not remove the block.
A person you have blocked cannot contact you directly; however, you might find yourself in a conversation with the blocked person if you are both invited to the conversation by someone else.