What kinds of things do people do with this?

I am going to post a ton of examples here over time. To be getting on with, The Norwegian police department does shift assignments for their personnel based on experience, union rules, etc. A company in Japan used rules to control security clearances in a “smart office building.” A truck manufacturer uses rules to determine what kinds of parts can be placed on the basic assembly frame and where they should be positioned for the assembly process. Rules look for fraud, they spot people who haven’t filed tax returns, they react to automatic diagnostics on manufactured parts, they help insurers crawl through a ship’s hold while inspecting it for seaworthiness (and so on ad infinitum).