It's a term that involves peeking inside the reporting process, something that journalists culturally aren't usually much willing to do. But it's a concept that suggests technology now makes it possible to share the effort and not just the results of journalism.
It makes people feel part of the process --- indeed, it uses non-journalists in the process through Twitter (something Winer believes is at least a dress rehearsal for the future) --- and still protects the journalist from criticism for premature distribution.
In essence, it says, here's what we are trying to know and here's what we know. And we're saying everything.