the Regional Boards.
The regional boards are where hobbyists and providers from a specific area meet and talk. ISO's are specific to an area in nearly every instance.
Local hobbyists and providers can help those with ISO's find what they are looking for, which does not seem to happen so much on the national ISO board. Local knowledge helps both hobbyists and providers.
A lot of ISO's are from Alias' and no-review (risky) posters. Local guys and gals have an incentive to call out some of these posts for mutual safety and protection from LE and people with something to hide, or offer advice on how to post an ISO in a better and less suspicious way. Less such incentive on a national board, IMO.
The national ISO board is just another board to search and sift through; local boards are more relevant for everyone and don't require changing boards and looking at 10x more irrelevant posts for every individual. Local boards are relevant, whether for conversational topics or ISO's.
The national ISO board is not locally relevant, fails to collect most ISO's and is less useful and safe than local boards. Many local boards would have few or no posts without ISO's - and some are otherwise dead anyway. It's not like ISO's clutter an otherwise dead board.
I say kill the national ISO board and put locally-oriented posts (including ISO's) on the local boards. Simplify this site, make it more effective/efficient for the needs it serves and the users, and increase utilization of the local boardss