I have been trying this at work, and though it started out a geek-fun it seems to really keep things clear and short.
eg:
status: 200, priority: 5 message: [ @all: 'this message is for everyone on the list', @user1: 'something special for user1 only' ], links: [ { url: 'http://www.brightcove.com/en/why-brightcove', message: 'updated version' } ]
What does everyone think? Does this really work in general or do I work with a uber-geeky crowd?