blog search by google

finally, google unveiled its blog search. it's basically based site feeds i.e. RSS and Atom etc.
one question that i have is how it will handle posts that are not in the feed? for example, there are too many posts during google's crawler's indexing interval. so some post will not appear in the feed.
another situation is after being indexed, the post gets updated or deleted. how does it know when to update the page?
let's see how it goes. at least it's better then none.