friendsBoard is a simple communication tool for groups. Write messages to a board, either via the web interface or the windows client, which members of the same board can instantly see. Each board's message history is permanent. The web interface uses ajax, so you never have to manually refresh the board you are viewing - messages will simply appear as members submit them.
friendsBoard is forever free for any use.
Example of a friendsBoard conversation
Android and iPhone browsers are supported(ish).
When viewing a board your friends on that board will appear here.