Have a look at the messaging coding link that I posted earlier.

It really simplifies messaging, so (for example) you can do something like:
  • On the "server" side push a new mesage onto a queue and set an expiry time - for example 24 hours for a reason-for-outage message, 1 week for an alert about planned downtime, 10 minutes for notice that fire alarms will be tested in 10 minutes time.
  • On the client side, poll the queues that you are subscribed to and display any new messages
  • Use different queues for different roles - you may have an IT engineers queue, a local building queue and a corporate queue