You may add a Contact to your Yahoo! Messenger by doing the following:
You can also add someone from the Contacts menu:
1. Go to the Contacts menu and select Add Contact.
2. In the window that pops up, add the contact's Messenger ID. You can also put the new contact into a group and add contact details.
3. Include a short message to the new contact, if you want.
4. Click Add when you're done.
♦When you add a contact to your list, the person is automatically notified and given the choice to allow or deny the add request. If the contact denies your request, this person will not appear in your Messenger List.
Note: If you are having trouble adding a contact, make sure that you are using the person's exact Yahoo! ID. If you still have problems, please let us know. Please include the Yahoo! ID in question.
Best of Luck to You.