Aside from the official McDougall forums, a lot of people have no idea where to find other people who are following the McDougall Plan.
There's a list of bloggers who are/were recently/plan to following McDougall on my Bloglines RSS feed page which includes:
McDougalling With Chile
Rites of Passage
Fun Crunch Files
Jill Nussinow's Green Cooking with A Pressure Cooker (A McDougall Celebrity Chef and pressure cooker genius)
Jennifer McCann's Vegan Lunch Box (mostly eat to Live lately but still McD-legal)
The McDougall Community on LiveJournal.
McDougall Chat on Yahoogroups
McDougall Weight Loss Plans Yahoogroup
Susan Voisin's Fat Free Discussion Board
McDougalling Community on Facebook
McDougall Friendly Recipe Wiki which as much more than just recipes
Dr. Neal Barnard's Get Healthy Club on PCRM
and there's a whole slew of McDougallers on the Post Punk Kitchen forums
I think we have a pretty prolific presence out there, wouldn't you agree?