Moderate nothing. Let the ignore button do it's job.
Make a new sub-forum for each of the major manufacturers and 1 more for any new entrants to the bitcoin mining marketspace. They can be promoted to their own new sub-forum if they make it bigger and appear not to be a scam.
+1.
-1
It's not the forum mods' job to legitimise one manufacturer over another by giving them their own subforum.
Given the amount of frauds and outright fakes that have collected funds and vanished by announcing their wares on bitcointalk.org, it might be time for the mods to at least differentiate between vetted and unvetted products and services. Perhaps such scrutiny might avert a future Pirateat40 or two.
As it stands now, as long as someone doesn't anger the community, they are free to emulate Bernie Madoff to their hearts content.