I like the idea of an "emergency broadcast system" which can be used to push single-line messages out to all *.maemo.org users.

However, the "all *.maemo.org users" bit is a big technical problem. There are multiple servers and sites all working together which'd somehow need to talk to one central server. The easiest way to accomplish this is probably a piece of JavaScript which is hooked into the MediaWiki template, the Bugzilla template, the vBulletin theme, the Midgard styles, Garage and so on.

This JavaScript could then add the current message, if any; without having to coordinate updates and communication at the server level between these disparate services.