This might be a good basis to use as a start onto an instant message hack where this window would pop up with the message you send them from a list of choosable users online at that moment.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.