A user who has signed on to an online gaming service can send an invitation to a friend appearing in the user's friends list to join in playing the game the user has loaded or may join the friend in playing the game being played by the friend, regardless of whether the game title played by the friend...http://www.google.com/patents/US7311608?utm_source=gb-gplus-sharePatent US7311608 - Online game invitations using friends list
