Moodlerooms is proposing the inclusion of two new message output into Moodle. These outputs are Steams and alerts. The specification can be found at http://docs.moodle.org/dev/Streams_and_alerts.
We would welcome any comments on the specificaiton and will be adding a technical specification as well. We have already developed streams and alerts and it has been in use by our clients for a year and a half. We beleive that these message outputs will bring a less invasive notificaiton system to Moodle than popups, but more invasive than email messages. below is a video of the current working version of the message output.