Welcome to Usermessages, a way of sending a message to multiple users at once without editing all of their talk pages, saving time and space on their talk pages.
In order for this to work, all users involved must use this template on either their user or user talk pages. If you plan on being "connected", find a place for this template (which will only show a table) and add it in. The table is plain – you can add an alignment (default center, parameter 1), background color (parameter 2), a border color (3), a text color (4) and a width (default 75%, 5) to match your user page style ({{usermessages|left/center/right|#RRGGBB|#RRGGBB|#RRGGBB|##%}}). It is up to the user to check his/her messages, which appear in the table.
You are free to edit the actual template, hidden normally to make your new message. Spread the news around to add {{usermessages}} so that the system is complete.
Note. These messages are in no way private from the public eye. Any users using the template will see the message. Do not include any personal information or anything you do not want made public. Finally, only users using the template will see the message.