It's not simple to explain everything involved, so I'll refer you to CEO Scott Karp and his excellent description. You can read his introduction to the service here, including this snip:
Here’s the short version: Publish2 is a social network and 2.0 platform for journalists (and independent “news bloggers,” “citizen” journalists, student journalists, i.e. ALL journalists, BROADLY defined), which aims to put journalists at the center of news on the web by creating a journalist-powered news aggregator.
You may also notice that I'm listed as an "advisor" to the project, which is right. I started talking about it with founder Robert Young early on, and I've been enthusiastic about the concept ever since. In my view, the idea has gotten better as they've refined it, and I think you'll be interested.
I'm going to ask a couple of McClatchy operations to participate in beta-testing, so you may be hearing from me.