In computer security "zero day exploits" are real world security problems occuring the same day the defect that makes them possible is announced.
It just struck me that what blogs do compared to the real media (you know, with reporters and research and press conference access) is to reverse the time flow of serious news stories: It used to be the case that we got the news in the abstract politicized form on weekdays ("Israel bombs Beirut", "Terrorist plot against Angle-US airflight thwarted) when they happened and then the newspapers would have a human interest angle for the sunday magazine ("Joan Sullivan was on her way, 3000 miles away from home, but she wasn't going to get any closer than that for the next couple of days").
Blogs reverse the news so the human interest story gets frontloaded. For a recent example, I read Doc's airport story at the same time as, or even before, I read about Heathrow closing and all Anglo-US transcontinental flights being grounded.
Access still matters. The mainstream media is much better at reporting the birds eye view of the story than most bloggers, but the way the wake develops as the story drops is completely changed.