For a brief explanation/exploration, check out the Beatblogging post where David Cohn puts it like this:
“Think of it as a Poynter 2.0: There is a core niche of journalism, but it is a space to connect to other people and share important ideas and information with them. It could have a tangible benefit to their work.”
It’s the “tangible benefit” part that excites me the most about this and inspired me to start drawing up plans for ReportingOn, which I envision as something closer to Twitter-for-journalists and Digg-for-readers rather than the Digg/Delicious sweet spot that Publish2 is trying to hit.
The thought of reporters strewn all over the city/state/country/world sharing notes on issues and building up context for local stories is The Right Idea; it’s what the Web is for.