I could see this being really useful if it could message a javascript event bus. Maybe use it for deciding when to synch browser data with server data or to modulate the messaging between different users browsers. The statelessness of http creates many timing related problems.

On a side note: when is one of these big companies going to release a really advanced "jquery for webkit" that forgets about the browser incompatibilities and focuses on building a virtual operating system in the browser? Google, Apple, Netflix? Anyone?