Unless you recruit mainly via this new job board I can hardly see why employers would go for it, it would just show a very small percentage because you fill most openings via LinkedIn or whatever, damaging the company branding.
I never said percentage.
"<small_boutique_company> has filled 8 verified positions on <product_name>"
Not a bad idea. Has the added benefit of giving a signal if the position/company has a turnover issue