To view the list of people who can see you (from Outlook Express)

1. On the Tools menu in Outlook Express, point to the name of your messenger service, and then click Options.
2. Click the Privacy tab. The My Allow List contains all the people who can see your online status and send you messages.

When you grant permission for your name to be added to someone's contacts list, you are putting that person's name in your Allow list. If you deny permission, that person's name will go in your Block list.

Block someone from sending you an instant message (from Outlook Express)

Unblock someone you have blocked (from Outlook Express)