Mystery Shopping is defined by wikipedia as ” a method used externally by market research companies or watchdog organizations, or internally by companies themselves, to measure quality of service, or compliance with regulation, or to gather specific information about products and services. ”
All I know is it is fun and rewarding. You get the opportunity to go to places you may or may not normally visit and get rewarded with products, gift cards or cash!
Some companies now have work at home Mystery Shopping opportunities available.