At the moment, "ISO" postings on the Chicago general forum seem to have enough critical mass to warrant their own forum.  (I know that there's already a regional-free "In Search Of" forum, but the regional discussion groups still have a lot of "ISO".)  Personally, if I have a few minutes to follow discussions on topics related to my region, I don't want to have to wade through a bunch of "ISO" postings.  "ISO" postings seem to be their own distinct category.

it is my understanding that TER will move them..there are a shitload of them though..

The ISO board is for all ISOs. When there were board moderators, they were supposed to move ISO posts form the regional boards to the ISO board. Now that there are no mods, TER depends on the report a post function. Apparently nobody in Chicago is reporting the ISO posts to have them moved.