I've noticed a real moblog effort from both "Emerging Churchers" and the Reformers who loathe the movement since I joined the blogosphere two months ago. The funny thing is this is not new problem, and I get the sense nobody is arguing with the same terminology. Postmodernism connotates too many things, and I think even postmodernists would agree they are not at all on the same page with each other.
I'm not an expert, but I have a unique understanding of this evolution. I've had my ear to the ground on this since 1995, when I was a young, idealistic college student who wanted to find a way to reach people my own age.
I can't offer you the be-all, end-all definition or history of postmodernism because nobody seems to agree what that is. At the risk of offending everybody, I suggest Andy Warhol is the father of today's perception of postmodernism. At least he popularized the idea, even if he is not actually considered a postmodern artist. Warhol was self-aware in his art as well as his day's culture, which is imminently post-modern. He was also a blender of pop culture, a borrower of pop culture. I remember the postmodern art fad in the late 80s/early 90s that fizzled because it was self-consuming pop culture. Postmodern artists tended to revile their own movement. It was destined to become a parody of itself.
Postmodern philosophers tend to be French, not very well read, and even less understood (according to them). Of that group, I'm most familiar with Jean-Francois Lyotard, who became well known in the late 70s and early 80s. If he was to speak to today's charge of relativism, I believe Lyotard would draw a very big distinction. Relativism is the refusal to accept any truth, I think he would argue, while postmodernism would simply be available to all considerations. (This is my best guess from the material I've read of him). From a modernist point of view, however, that distinction can only exist in a relative world.
Today's academic postmodernism is understood by me to be a "cult of one." It is the ultimate in individuality because it means my truth is my truth, regardless of the conflicts it might have with your truth. It is an open contract to agree to disagree. To this extent, I think this is the banner under which many who call themselves postmodernists today reside. They have their Christian thinkers, and they are firmly within the extreme left.
But not all of them can be categorized this way, and some "postmodern Christians" are not about postmodern philosophy at all (or acknowledge such a thing has merit). When some "postmodern Christians" refer to their postmodern point-of-view, they are talking about emphasizing postmodern values, like multiculturalism. To them, postmodern Christianity knowledge is about context, and delivery of knowledge is an ontological impression supplied by the Holy Spirit. This subset may not reject Biblical truth, but it is a very shifty sand when removed from the concrete modernism it denies. This subset might suggest we could learn as much truth from church tradition as we could from Biblical theology.
Then there is a third group of postmodern Christians that are unfairly dragged through the mud because of their unwitting association to the other two groups above. These Christians share a theology with Reformers, but want a methodology that is culturally relevant. They want to be to the world's margianlized youth what the Jesus People and the Third Wave were to Baby Boomers. It's nothing more than church growth in a poorly-labeled package. To this group, postmodernism is about relationship and reaching a culture that has more that has never been churched than those that have. Their philosophical "text" might be "Life After God," one of my favorite books. In this book, the main character reflects on an empty life based on agnosticism passed down from his parents. His insightful and honest reflection compared to his flawed relationships causes him to realize his sinful nature. He relents to God and undergoes his own private baptism. This is the kind of person this group intends to reach, a person they do not believe can be reached by conventional or "modern" churches.
Further causing confusion is the attempt to make academic what refuses to be normative. The language of postmodernism might was well be Martian -- and none of the native speakers are from Mars. One uses words -- even invents pseudo-academic words -- that bears meaning only to oneself, then attempts to convey the vague meaning of the word through context and conceptualization (two key ingredients to postmodernism). If three postmodernists discussing their philosophy with each other sound like a trio of "short bus" students pretending to be smart ... apologies if I'm imposing my truth onto yours with that assessment. These are extremely bright people lost in their own hopeless thoughts of being a part of something new and distinct.
As it relates to the Church, I think there is more room for grace for some EC members than what some critics have afforded them. If by Emerging Church, we're talking about a group of people taking classic Christianity to the marginalized, these people should be supported, not bashed. Forget that it's not really postmodern, that's just a term that they've co-opted without realizing the baggage they were taking on. Take away the piercings and the sofa-turned-pulpit and they are us.