I found what I think is the forum with the smallest amount of posts:
Activism: Peacemaking & Community Group, 63 posts
Last post was in January of this year.
Okay, this is rather a larger enterprise than I thought it would be, rating the traffic on the various forums on Skins's island.
This is just a 
small part.
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    146 comments HIV/AIDS Support Group 
    203 comments Single Payer Health Insurance Support Group 
    428 comments Deaf/Hard of Hearing Group 
    607 comments Smoking Cessation Group 
 1,185 comments Asperger's/PDD Group 
 1,862 comments Cancer Support Group 
 3,907 comments Chronic Health Conditions Discussion and Support Group 
 4,542 comments Weight Loss/Maintenance Group 
 8,588 comments Exercise and Fitness Group 
10,470 comments Mental Health Support Group