Just as the mainline is catching up to the idea that there is something called the "Emerging Church", the so-called Emerging folks have been experiencing something akin to a civil war over defining the post-evangelical church.
On the one side are the Emergent folks, namely Brian McLaren and Doug Pagitt (A Christianity Worth Believing). On the other side are folks who originally identified as "Emerging" but who seem to believe that the Emergent Church movement has strayed too far from orthodoxy; the best known of these is Mark Driscoll. Here are some decent links to read up on the argument: a noted blogger bids farewell to Emergent and Scot McKnight (author of The Blue Parakeet) calls out Brian McLaren.
What these "post-evangelicals" originally had in common was a dissatisfaction with the state of the evangelical church, which they saw as too fixated on the building of institutional megachurches, over-emphasizing salvation in the next life, lacking any real concern for the mission of Jesus to proclaim good news to the poor and the oppressed in this life. Both retain a concern for serving the least among us. But the central debate is about the core doctrines of Christianity. The "Emergence Christianity" folks seem to be willing to put everything on the table doctrinally while the neo-Reformers (see The Gospel Coalition) want to retain the core doctrines of the church while rethinking how we "do" church.
It's an interesting battle.