Google Hotpot is a recommendation engine for places and restaurants. It's Google's equivalent to Yelp, a popular restaurant rating site that Google attempted to acquire before negotiations between the two companies fell apart. Rather than buying a product that was ready out of the box, Google built their own.
You can use Hotpot to rate and publicly comment on local businesses on that location's Place Page. In turn, Hotpot offers recommendations for new locations based on your previous ratings, much like Netflix makes guesses on how well you'll like new movies. Hotpot also has a social aspect. It allows you to add friends, since many people share similar tastes for food or venues with their friends and want to see how their friends like a place before trying it for themselves.
Google Hotpot is on the Web at http://www.google.com/places/.
