Twitter and news: citizen journalism or background noise?

Every time something big happens in the world, we spend the following days reading about how amazing it is that the news was on Twitter way before its appearance on any other media.

And on Sunday it happened again: somebody had History outside his door, and tweeted about it in real time.  With no idea of what was going on. 
http://twitter.com/#!/ReallyVirtual/status/64912440353234944

My sensation is that this is often the case.  I am personally very interested in raw news coming directly from the field, but don't you agree that citizen journalism exists mostly "in hindsight"?

Gab