I generally use Yelp to post compliments to businesses who I think are doing a good job.
For those who aren’t, the forces of the market will eventually take care of that by themselves.
Almost twenty years after having to fire a worker I received a phone call from someone, explaining that the person in question gave me as a reference.
My response, with a rising inflection, was, "He DID?"
The caller said, "Thanks, that's all I need to know".