InterFace
Chat Messenger - Open Source Social Network - Online Chess Game
... defined (whitelisted) friends are allowed to post into the mailbox.
InterFace is the communication suite as well including a Forum Function like a Bulletin Board.
InterFace is based on Qt and c++ and can easily be used as a Plugin-Tab in any Qt Frame Host or other Qt App. It is based and a clone of Lib RetroShare Messenger. Currently this Friendslist is used in the Qt Browser Dooble as a Tab. See http://dooble.sf.net for more.