I feel like Bookwyrm has proven the idea of a federated review platform. Could this be extended to local business reviews?
I vowed long ago to stop contributing to closed platforms such as on Google Maps or Yelp. Could a federated alternative be a good solution?
https://mangrove.reviews/ seems to have a lot of potential, but is not federated as far as I know.
I think the main difference between a small Bookwym instance and what you propose is that a business review site only becomes useful at a much larger scale and risk of someone manipulating it is also much higher.
I think it could work.
ActivityStreams (the vocabulary for ActivityPub) already has an object for
Place
that could be used here. Importing place data from OpenStreetMap (with potential to contribute back to it) could fill out the information.