I've steered away from purchasing services/products from forums for the last year because of being scammed (BHW WSO).
It's a tough one because I'd love to get more business from like-minded business owners.
With regards to platforms like peopleperhour and upwork, I also stay away from those because of scammers or poor work/customers.
The only one I use now is Fiverr because it's strict and you feel more safe. That's the only way a marketplace is going to work but i think thats a lot to manage for mp.
Maybe there is a safe way, but you need to think from both sides; the buyer and the seller.
How about directory listings we pay for, I'm in for beta testing that!
p.s. I love this forum, its quality, no-one seems to be hiding anything