T-C Greg Graham is featured in this First Person piece in EdWeek Teacher: Why I No Longer Use Groups in my Classroom. Here's a snippet:
I’ve contemplated the use of groups quite a bit, particularly as it relates to writing in the classroom. You see, "group work" is very common in my field—many writing teachers swear by it, as I did originally. The idea is to break students up into small peer groups and have them help each other along each stage of the writing process. In the beginning of the process, they bounce ideas off each other, and as their work progresses, they read one another’s writing and give feedback.
When asked to articulate my philosophy for teaching writing near the end of my time in graduate school, I wrote this:
"Though I was initially resistant to the idea, you can sign me up as one who is going to be applying collaborative learning in the classroom, using groups to create what [Mary] Belenky calls a 'connected class.' It is my hope that through their connecting and sharing with one another, the students will be more engaged in the classroom, more engaged in the writing process, and more engaged with the world in which they live."
Ah, the idealism of a new teacher. Belenky, an advocate of collaborative learning, means many things when she speaks of the connected classroom. She means teachers serving as midwives drawing out their students' thinking rather than bankers depositing knowledge into them. She also means students "constructing truth through consensus," i.e., brainstorming. While I still embrace the ideal of the teacher as midwife, I no longer believe brainstorming peer groups are an effective way to develop students’ thinking. On the contrary, peer groups often have the opposite effect.
Check out the whole thing, including the New Yorker piece, Groupthink, he references, and share your thoughts about groups and group process in the writing classroom.

Responses
You'll find support for this concept in Jonah Lehrer's new book IMAGINE: HOW CREATIVITY WORKS. As an author and past classroom teacher—my master's project was on teaching writing, and I've done it ever since—a more flexible strategy is what worked best for me and my students. Students worked on their own or with others as they needed, not in a teacher-assigned group that is unusual in the real world. For instance, most students came up with ideas and wrote drafts on their own. If they got stuck, they might move to the side of the room with a friend or two to figure out a new direction.
When students finished drafts and wanted feedback, they could find others who also wanted to get critiques, and they'd meet together. I had several techniques I used to manage the chaos, but it was worth the effort. Even though teaching writing was my passion and area of expertise, it was still the hardest part of my day. The results, though, were amazing. Some of my students have moved on to be professional writers, journalists, and one is an award-winning news reporter.
In my work as a creativity coach, I've seen what a difference it makes when teachers are writing themselves. Passion brings out passion, and if you're a teacher, you understand the importance of kids seeing the adults around them reading. The same goes for writing. And writing with your students is a great way to show them how to be vulnerable and share your worst junk. If more teachers wrote, they would come up with more creative and realistic ways to support the writing process in their classrooms. And to those of you who do write with your class, congratulations and thank you!
You are so right that when teachers write -- and have a real relationship with writing as an intellectual and creative act -- they make different decisions in the classroom, fostering a more authentic environment for writiing.
I think finding some balance between the writer as a soloist and then the writer/readers as a member of a community is one way to go about it. Thanks for sharing that piece, though, because I, too, thought about the connection between the classroom and that Groupthink piece when I read it in New Yorker, and then promptly forgot about it. But it's message does still resonate and provokes the question that Greg asks about whether group configurations work for the individual writer (as opposed to creating a writing community, which is sort of different, right?)
I wonder, too, how the emergence of online communities might be changing our ideas around groups. In the classroom, we sort of form group work with a small number of people to choose from, so there are limits to the connections that any one person can make to each other. With online communities, you might open up the connections, so that a Manga writer might connect with other Manga writers while the class poets might find a real group of other poets, etc. Just something to be thinking about ...
Kevin