The two things that are great about a write-in are: 1) writing, and 2) not writing.
The basic theory, of course, is that we’re all getting together to place Butt in Chair with headphones on, and using the Power of Positive Peer Pressure to get some serious draft knocked out. (Oh yes, and it works: the sound of someone else tippytapping away is enough to generate reams of draft.)
The reason for the headphones is that we can have side-conversations and chat breaks without disturbing our fellows.
Almost all of my local writing buddies I met at write-ins, In Between Time. For example: just now had a great conversation with a NaNo colleague about the perilous art of beta-reading a first-draft and (more perilous yet) a work-in-progress that’s come to a stuck point. That second set of eyes can make the difference, but it’s a really tricky business.
Asking questions, reacting to the story as a reader, digging down and getting honest about emotional reactions… that’s the secret. Reminds me a bit of those Zen instructions for enlightenment, “Chop wood, carry water.” It’s completely simple, and a lot harder than it looks. (Most simple things are.) You reveal a lot of yourself in reacting to someone else’s story, just as you reveal a lot of yourself in writing your own. The talks about what we like to write, the territory we’re exploring, are really asking the question: Are you weird the same way I am?
In the meantime, in between time, ain’t we got fun… getting to know each other. And a shivery kind of fun it is, too.