Upon fulfilling an achievement's conditions, you will receive a notification at the top of the screen, and the reward will be sent to the present box. In addition to this, mail about your achievement will be sent to your friends.
- Received Mail: When you receive mail about your friends' achievements, choose a Stamp to reply with.
- Read Replies: You can see the stamps your friends sent in response to your achievement.
- Friend Points are rewarded for sending and receiving replies.
- Both inboxes can hold up to 30 items only. You won't receive new ones if there are 30 unread.
- Mail is randomly sent to a number of the user's friends, based on how many friends one has:
- 1 friend - mail is sent to 1 friend
- 2-5 friends - mail is sent to 2 friends
- 6-10 friends - mail is sent to 3 friends
- 11-15 friends - mail is sent to 4 friends
- 16+ friends - mail is sent to 5 friends
