I'm not sure I can answer for all writers in general, but I will happily answer this question for myself.
For me, finding the companionship of other writers has been absolutely crucial. I have no doubt, at all, that my first short story for the Loves Landscape Anthology would never have happened if I hadn't stumbled onto a writer support thread, during the event. Having the support of both new writers, as well as a few veterans, spurred me on to complete something that anxiety and intimidation had me seriously considering, giving up on.
I certainly owe a great deal to the handful of writers that I have grown close too over the last six months.
For me, at least, writing is a very solitary pursuit. And when I write, I often pull from past experiences, both good and bad, and it can be emotionally draining. I suspect this is true for most writers. Having a group of 'writer friends', people going through some form of the same thing, to get feedback from, relax with, and just kid around with, rejuvenates me.
Of course, the coolness of my writer friends is likely debatable. :P